Composite material

ABSTRACT

Systems and methods for composite materials, including coatings and stand-alone structures are provided. An apparatus may include a first layer structure that includes a first plurality of densely packed sub-macroscale particles having a first mean diameter; and at least a second layer structure that includes a second plurality of densely packed sub-macroscale particles having a second mean diameter that is different from the first mean diameter. The first layer structure and the second layer structure may be applied to a substrate, where the substrate may be an article of sports equipment, medical device or other article.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/667,764, filed Jul. 3, 2012; the contents of which areincorporated by reference herein in its entirety.

This application is a continuation-in-part of U.S. Non-Provisionalpatent application Ser. No. 12/672,865, filed Feb. 9, 2010, which is aNational Stage Entry of PCT/US2009/053462, filed Aug. 11, 2009, whichclaims priority to U.S. Provisional Patent Application No. 61/153,539,filed Feb. 18, 2009, and PCT/US2008/072808, filed Aug. 11, 2008; thecontents of each application are incorporated by reference herein intheir entireties.

FIELD OF THE INVENTION

The present invention relates to a composite material and, inparticular, to a composite material comprising one or more layers ofparticles.

BACKGROUND OF THE INVENTION

Material designs for handling the impact of an external stimulus, suchas a sports impacts, blasts or projectiles, include, for example, wovenfabrics, ceramic materials, and composite systems. KEVLAR, ZYLON, ARMOS,and SPECTRA are commercially available fabrics made from high-strengthfibers.

Particularly for sports impacts and other related actions, thetraditional approach has been to increase the size of protectiveequipment, develop new materials, and/or redesign the shape of theproduct. Needs exist for new systems and methods for improvingprotection against impacts in sports and other fields.

SUMMARY OF THE INVENTION

Embodiments of the present invention solve many of the problems and/orovercome many of the drawbacks and disadvantages of prior systems byproviding systems and methods for attenuating a shock wave or impact.

For purposes of the present invention, the terms “impact”, “blast”,“impact wave”, “shock wave” are used for illustrative purposes. It isunderstood that reference herein to, for example, a shock wave from ablast would apply equally to a wave from an impact from a sports impactor any other contact that creates a disruptive force, such as dropping,bumping, striking, jostling, crushing, flexing, etc. of an object.

Embodiments of the present invention may include a sports equipmentapparatus. The sports equipment apparatus may include a first layerstructure that includes a first plurality of densely packedsub-macroscale particles having a first mean diameter; and at least asecond layer structure that includes a second plurality of denselypacked sub-macroscale particles having a second mean diameter that isdifferent from the first mean diameter. The first layer structure andthe second layer structure may be applied to a substrate, where thesubstrate may be an article of sports equipment.

In certain embodiments, the first mean diameter may be greater than thesecond mean diameter. The first mean diameter may be less than thesecond mean diameter. The sub-macroscale particles may be selected froma group consisting of: microscale particles, nanoscale particles, andcombinations thereof. A selected one of the first layer structure andthe second layer structure may include solid particles. A selected oneof the first layer structure and the second layer structure may includehollow core shell particles that are configured to deform upon beingsubjected to the compression wave. A selected one of the first layerstructure and the second layer structure may include hollow core shellparticles that are configured to rupture upon being subjected to thecompression wave. A selected one of the first layer structure and thesecond layer structure may include liquid filled particles that areconfigured to release a liquid upon being subjected to the compressionwave. The sub-macroscale particles may include particles selected from agroup consisting of: polystyrene, silica and carbon. Embodiments mayinclude a plurality of adjacent layer structures, each of the pluralityof adjacent layer structures including a plurality of densely packedsub-macroscale particles having a corresponding mean diameter, theplurality of adjacent layer structures disposed so that a mean diametergradient is formed across the plurality of adjacent layer structures.The particles may be functionalized prior to deposition. The particlesmay include carboxylic acid functionality. The particles may bepolarized. Embodiments may include an intermediary layer including acomposite of polymer and carbon allotrope and may include an outer layerof the same composite.

Certain embodiments may include a method of making an article ofsporting equipment. The method may include depositing a first pluralityof sub-macroscale particles having a first mean diameter and suspendedin a first liquid medium onto a substrate; subjecting the firstplurality and the substrate to a first environment for a firstpreselected amount of time sufficient to cause the first liquid mediumto evaporate leaving a first layer structure of the plurality ofsub-macroscale particles on the substrate; depositing a second pluralityof sub-macroscale particles having a second mean diameter, differentfrom the first mean diameter, and suspended in a second liquid mediumonto first layer structure; and subjecting the second plurality, thefirst plurality and the substrate to a second environment for a secondpreselected amount of time sufficient to cause the second liquid mediumto evaporate leaving a second layer structure of the plurality ofsub-macroscale particles on the first layer structure, and wherein thesubstrate is an article of sporting equipment.

Certain embodiments may include the action of irradiating the substrateso as to create an organic acid functionality on a surface of thesubstrate, thereby increasing adhesion of the sub-macroscale particlesthereto. The sub-macroscale particles may include particles selectedfrom a group consisting of: polystyrene, silica and carbon. Thesub-macroscale particles comprise particles may be selected from a groupconsisting of: solid, hollow and core shell, filled, unfilled, andfilled in part. Certain embodiments may include the action offunctionalizing the sub-macroscale particles prior to deposition. Thefunctionalizing action may include providing the sub-macroscaleparticles so at to include carboxylic acid functionality. Thefunctionalizing action may include polarizing the sub-macroscaleparticles. The sub-macroscale particles may include particles selectedfrom a group consisting of: nanoscale particles, microscale particlesand combinations thereof.

Certain embodiments may include a medical device apparatus. The medicaldevice apparatus may include a first layer structure that includes afirst plurality of densely packed sub-macroscale particles having afirst mean diameter; and at least a second layer structure that includesa second plurality of densely packed sub-macroscale particles having asecond mean diameter that is different from the first mean diameter,wherein the first layer structure and the second layer structure areapplied to a substrate, and wherein the substrate is an article ofmedical equipment.

Certain embodiments may include a sports equipment apparatus. The sportsequipment apparatus may include a layer structure that includes aplurality of densely packed sub-macroscale particles having a first meandiameter, wherein the first mean diameter is approximately 150 nm,wherein the layer structure comprises at least approximately 30 layersof the particles, wherein the layer structure is applied to a substrate,and wherein the substrate is an article of sports equipment.

The invention may be based in part on the fact that a composite materialwith a structure that includes microscale particles that can interactwith each other can absorb, distort, and/or redirect the force of animpact, such as, e.g., blunt force trauma, mild traumatic brain injury(mTBI), and other traumatic brain injury (TBI). The invention is furtherbased in part on the fact that a composite material with a specificgradient layer structure can absorb, distort, and/or redirect acompression wave, such as, e.g., a shock wave accompanying a sportsimpact or an explosion. The invention is also based in part on the factthat a composite material with either solid, hollow and core-shellparticles, separately or in combination, can absorb, distort, and/orredirect a compression wave, such as, e.g., a shock wave accompanying asports impact or an explosion. In general, composite materials (orcomposites) are engineered materials made from two or more constituentmaterials (e.g., solid particles, hollow particles, core-shellparticles) with significantly different physical and/or chemicalproperties that retain their separate and distinct physical and/orchemical identities within the finished structure.

The invention may be further based in part on the fact that a compositematerial with a gradient layer structure comprising particles withvarying size arranged to form a gradient of the particle size mayprovide increased hardness (relative, e.g., to a material not innanoparticle format) and shock absorbing features when smaller or largerparticles form the surface of the composite material or at least aninteracting side of the composite material.

The invention may be further based in part on the fact that a compositematerial may provide upon activation specific reactions and/or materialsto its environment. For example, the composite material and/or at leastone of the materials constituting the composite material can be furtherdesigned to mitigate and/or remediate primary and/or secondary effectsresulting from a compression wave. Thus, some embodiments of the presentinvention can provide novel composite materials that through intelligentdesign of the composition of the materials and a structure within thecomposite material can not only reduce (mitigate and/or remediate) theimpact of a shock wave (primary blast effect) with greater efficiencyand efficacy but that can also mitigate and/or remediate one or moresecondary blast effects. Thus, other embodiments of the presentinvention can provide novel composite materials that through intelligentdesign of the composition of the materials and a structure within thecomposite material can not only reduce (mitigate and/or remediate) theimpact of a sports impact (blunt force) with greater efficiency andefficacy but that can also mitigate and/or remediate one or moresecondary force of impact effects (mTBI and TBI). Moreover, thecomposite material and/or at least one of the materials constituting thecomposite material can be, for example, further designed to be activatedthrough a chemical signature in its environment or through a physicalcondition (e.g., of a compression) wave to change a physical and/orchemical property such as color.

The invention may be further based in part on the fact that a compositematerial may use a compression wave to work against itself to mitigateand/or remediate the primary and secondary effects of the compressionwave. Similarly, when an incident shock wave is reflected from thecomposite material, the reflected shock wave can be distorted. When theincident and reflected shock wave form a combined shock wave, primaryand secondary effects of the combined shock wave can be mitigated and/orremediated due to the distortion of the reflected shock wave.

In a first aspect, the invention may feature multilayer compositematerials that include a gradient layer structure of a sequence of atleast three gradient-contributing layers of microscale particles,wherein a mean particle size of particles of neighboringgradient-contributing layers in the cross section of the gradient layerstructure can vary from layer to layer, thereby forming a particle sizegradient, and in contact with the gradient layer structure, a denselypacked particle structure including densely packed microscale particles,wherein a mean particle size of the densely packed microscale particlesdoes not form a particle size gradient in the cross section of thedensely packed particle structure. In another aspect, the inventionfeatures methods that include attenuating a compression wave using acomposite material. The particles may be free to move relative to oneanother to transfer momentum to neighboring particles within a layerstructure and between layer structures.

In another aspect, the invention may feature liners that include amultilayer composite material.

In another aspect, the invention may feature receptacles that include amultilayer composite material.

In another aspect, the invention may feature systems that include apipe; and a multilayer composite material.

In another aspect, the invention may feature helmet liner pads thatinclude a multilayer composite material.

In another aspect, the invention may feature helmets that include ahelmet structure and a multilayer composite material. Other sportsequipment may be included in embodiments of the present invention. Thesemay include protective gear, sports equipment, balls, etc.

In another aspect, the invention features textiles that include amultilayer composite material.

In another aspect, the invention may feature transportation devices thatinclude a body and a multilayer composite material.

In another aspect, the invention may feature composite materials thatinclude a multilayer composite material, wherein the composite materialincludes a color changing sensor material.

In another aspect, the invention may feature a safety structure thatincludes a pair of structural elements and a multilayer compositematerial.

In another aspect, the invention may feature multilayer compositematerials that include a first substrate and a layer structure of asequence of layers of microscale particles in contact with the substrateat a first face of the layer structure, wherein at least one layer ofmicroscale particles includes core-shell particles, the layer structureincludes a region of neighboring layers that form a gradient layerstructure such that a mean particle size of particles of the neighboringlayers varies along the cross section of the gradient layer structurewithin a range of particle sizes, and the gradient layer structure formsa second face of the layer structure opposite to the first face of thelayer structure with particles having a size at the lower end of therange of particle sizes.

In another aspect, the invention may feature multilayer compositematerials that include a gradient layer structure of a sequence oflayers of microscale particles, wherein a mean particle size ofparticles of neighboring layers in the cross section of the gradientlayer structure varies from layer to layer, thereby forming a particlesize gradient and at least one of the layers of the gradient layerstructure is configured to have a thickness larger than a mean particlesize of the particles of the respective layer

Embodiments of the aspects can include one or more of the followingfeatures.

In the multilayer composite material, a thickness of the gradient layerstructure and a thickness of the densely packed particle structure canhave a ratio of thickness in the range from 0.1 to 10.

The particles can include at least one particle selected from the groupconsisting of solid particles, hollow particles, andcore-shell-particles.

The multilayer composite materials can further comprise at least oneadditional gradient layer structure and/or densely packed particlestructure and wherein the gradient layer structure, the densely packedparticle structure and the at least one additional gradient layerstructures and/or densely packed particle structure are arranged as asequence, where neighboring structures contact each other at a commoninterface. In some embodiments, the gradient layer structure is a firstgradient layer structure having a first particle size gradient in afirst direction and the composite material further comprises a secondgradient layer structure having a second particle size gradient in thefirst, opposite to the first, or in a third direction.

In some embodiments, the gradient layer structure can include at leastone layer with a particle size smaller than 1 mm, 0.1 mm, 0.04 mm, 1000nm, 500 nm, 100 nm, or 10 nm.

In some embodiments, the gradient layer structure can include at leastone layer with a mean deviation below about 10% for a median particlesize distribution.

In some embodiments, densely packed microscale particles of the denselypacked particle structure can be at least partly arranged in a layerstructure.

In some embodiments, the layer structure of the densely packed particlestructure can include at least one layer with a particle size smallerthan 1 mm, 0.1 mm, 0.04 mm, 1000 nm, 500 nm, 100 nm, or 10 nm. The layerstructure can include at least one layer with a mean deviation belowabout 10% for a median particle size distribution.

The method can include forming a sequence of particle layers such that agradient of the particle size over the sequence is defined as a changein size of particles populating different individual layers.

The method can further use composite materials that include at least onea core-shell particle, which contributes to the attenuation of thecompression wave. In some embodiments, energy absorbed with the at leastone core-shell particle is used to release a core material from thecore-shell particle. The methods can further use composite materialsthat include at least one hollow particle, which contributes to theattenuation of the compression wave. In some embodiments, there is anincrease in the energy absorbed with the at least one hollow particleused.

The composite material can be used in various configurations including acoating, e.g., sprayed to an underlying substrate, a film (attachable tosurfaces or free standing), a foil, a panel (e.g., molded from thecomposite material), powder or granular material (e.g., used as afilling material of hollow panels), or any structure made completely orto a large extent from the composite material. Some configurations caninclude a binding layer on the surface of the composite material whichmay include carbon allotropes. Some configurations can include a bindinglayer in between layers of the composite material. In addition, oralternatively, an intermediary material can be included within thecomposite material in between the particles, which may include carbonallotropes.

In some embodiments, the particles can be sufficiently polar to holdtogether by themselves so that for the composite material no bindinglayer or intermediary material is needed.

In some embodiments, the gradient layer structure can be configured suchthat a change in particle size between neighboring layers of thegradient layer structure ranges from 5% to 50% of the mean particlesize. The particle size of neighboring layers can change by at least 5%,10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. The particle size ofneighboring layers can increase or decrease. For example, the gradientlayer structure can include at least a first layer with a first particlesize smaller than 1 mm and a second layer with second particle sizesmaller than the first particle size.

In some embodiments, a number of contact points per area betweenparticles within neighboring layers can change according to the particlesize gradient. The contact points can to some extent be “potential”contact points in a less densely packed layer.

In general, a layer includes particles of similar size. Specifically, alayer (and thus the particles of the layer) is characterized by a meanparticle size. A layer can have generally any shape and configuration.

In some embodiments, at least one layer can be a layer of mono-dispersedparticles (herein also referred to as mono-dispersed layer). Thethickness of such a layer can be about the mean particle size of theparticles of that layer. The particles of the mono-dispersed layer canbe densely packed, i.e., most or all of the particles are in contactwith neighboring particles of the mono-dispersed layer. Alternatively orat least in some regions, the particles can also be loosely packedthereby providing available volume in between neighboring particles thatcan be filled with other particles.

In some embodiments, the thickness of at least one of the layers can belarger than the mean particle size of that layer. Herein, such a layeris also referred to as a multi-particle layer and “multi-particle”refers to a thickness given by multiple particles being positioned alongthe direction of the cross-section of the layer. A multi-particle layercan be understood to include two or more sub-layers each of whichcorrespond essentially to a layer of mono-dispersed particles. Thus,such a multi-particle layer has a thickness that is larger than thethickness of a layer of mono-dispersed particles (of the same type).

In some embodiments, a multi-particle layer can include two or moredensely packed sub-layers wherein the particles contact neighboringparticles within the sub-layer. Then, the overlap of neighboringsub-layers is mainly given by the geometry of the particles. Ifneighboring sub-layers are loosely packed, sub-layers can overlap eachother to some extent.

In some embodiments, a multi-particle layer can include two or moreloose packed sub-layers. These sub-layers can overlap in direction ofthe cross section of the sub-layers such that the combined thickness oftwo overlapping sub-layers is less than twice the thickness of onesub-layer. In embodiments of overlapping sub-layers, particles in eachsub-layer may not be in contact with each other but particles of onesub-layer can be in contact with particles of the other sub-layer. Ingeneral, the thickness of the two sub-layers can be more than the meanparticle size of the particles of the sub-layers and is generally lessthan twice the mean particle size of the sub-layers.

In some embodiments of a multi-particle layer, a layer can include atleast two or more particles in direction of a cross-section of thelayer.

In some embodiments, the particles within at least one of the layers canbe in contact with each other (or at least being able to contact eachother upon impact of a compression wave).

In addition, the particles of neighboring layers can be in contact witheach other or at least being able to contact each other upon impact of acompression wave.

The densely packed particle structure can be configured with particleshaving a size range from 5% to 500% of the mean particle size. Thedensely packed particle structure can include at least 25%, 50%, 75%, or100% core-shell-particles.

Within the densely packed particle structure, a number of contact pointsper area between particles within a region can change along the crosssection according to the size of the particle.

The particles of the densely packed particle system can be arranged in anon-gradient layer structure. At least one of the layers of thenon-gradient layer structure can have a thickness larger than a meanparticle size of the particles of the respective layer. The at least onelayer having a thickness larger than a mean particle size can beconfigured to include at least two sub-layers of particles.

At least one of the two sub-layers can be densely packed such thatneighboring particles are in contact with each other within the at leastone sub-layer. At least one of the two sub-layers is loosely packed suchthat neighboring particles are not in contact within the sub-layer. Atleast one of the two sub-layers can be loosely packed such that itsparticles are in contact with particles of a neighboring layer. At leastone of the two sub-layers can be loosely packed such that its particlesare in contact with particles of a neighboring sub-layer. At least twosub-layers of particles can overlap partially.

The thickness of the at least one layer having a thickness larger than amean particle size is larger than or equal to about twice, three-times,four times, five times, six times, seven times, eight times, nine times,or ten times the mean particle size of the respective particles of thatlayer. The thickness of at least one of the layers of the non-gradientlayer structure can be about the mean particle size of that layer.

In some embodiments, particles of the gradient layer structure and/or ofthe densely packed particle structure can be in contact with each other.

In some embodiments, particles of the gradient layer structure and/or ofthe densely packed particle structure are positioned with respect toeach other such that at least some of the particles get into contactwith each other during interaction with a compression wave.

In some embodiments, the particles or at least some of the particles ofthe gradient layer structure and/or of the densely packed particlestructure are configured for unrestrained interaction between particles.

The particles can be configured for unrestrained movement and thereforeinteraction upon actuation, e.g., impact of a compression wave. Theparticles can be loose and unrestrained to allow moving and transferringmomentum to neighboring particles.

The composite material can include, for example, as a layer, solidparticles, hollow particles, core-shell-particles, microspheres, andspherical particles.

The gradient layer structure can include at least one layer with aparticle size smaller than 1 mm, 0.1 mm, 0.04 mm, 1000 nm, 500 nm, 100nm, or 10 nm.

The particles can provide essentially elastic interactions betweenneighboring spheres thereby enabling momentum distribution whentransferring momentum from one of the layers to a neighboring layer viathe particles. The mass of the particles is configured to allow no delayin reaction to a compression wave.

The gradient layer structure can include at least one layer with a meandeviation below about 1%, 5%, or 10% for a median particle sizedistribution.

The particles can be dispersed in a resin that allows momentum transferto neighboring particles.

The gradient layer structure can include an intermediary material, e.g.,for binding particles and/or layers together. The intermediary materialcan fill, for example, at least partially a volume surrounding theparticles.

In some embodiments, the particles attach to each other without anyintermediary material.

The gradient layer structure and/or of the densely packed particlestructure can include a pore microstructure, which is at least partiallyfilled with air, gas or an intermediary material. The intermediarymaterial can be a material of the group consisting of ionomers,polymers, polymerizable monomers, resins, and cyclodextrins.

The gradient layer structure can be a first gradient layer structurehaving a first particle size gradient in a first direction and thecomposite material further comprises a second gradient layer structurehaving a second particle size gradient. The first and the secondgradient can be directed in the same or in the opposite direction withrespect to the layer structure. The composite material can furthercomprise a third gradient layer structure having a third size gradientin the direction of the first or second gradient structure.

The multilayer composite material can further include a substrate andthe gradient layer structure or of the densely packed particle structurecan be applied to the substrate. The substrate can be a housing, e.g., ahousing of an electrical device, a helmet, a helmet liner, a helmetliner pad or pads, a waste receptacle, a pad, a frame, a wall, a panel,a waste receptacle liner, a liner, sports equipment such as a helmet,racket, shaft, stick, rod, club, bat, glove, mask, pad or otherprotective equipment, a ball, a soccer ball, a baseball, a football, agolf ball, a thread, textile, cloth, cladding of a pipe, e.g., for apipeline, and the surfaces of vehicles, vessels and crafts for land,sea, and aviation, side walls of a safety window (e.g., made of polymeror glass or a combination thereof) etc.

Materials of the substrate include, for example, substrates providing apolar surface. Glass, Poly(vinylchloride), nylon,Poly(methylmethacrylate), Poly(vinylpyridine), and Poly(vinylphenol)can, for example, provide a polar surface. A polar surface can, forexample, be caused by an acid functionality at the surface. Somematerials can provide a polar surface after a special surface treatmentsuch as UV irradiation.

Additionally, various materials can be coated with a polar coating. Anexample of a polar coating is a coating that includes polar particlessuch as carbon nanoparticles with a phenylsulfonic acid functionality ontheir surface.

Additionally or alternatively, any of the polymers listed above can beused as coating material.

The multilayer composite material can be configured as a self-supportingstructure. The structure can have the form of a housing, e.g., housingof an electrical device, a waste receptacle, a pad, a frame, a wall, apanel, a waste receptacle liner, a liner, a bag, a foil, sportsequipment such as a helmet, racket, shaft, stick, rod, club, bat, glove,mask, pad or other protective equipment, a ball, a soccer ball, abaseball, a football, a golf ball, thread, textile, cloth, a helmetliner pad or pads, a helmet liner, structural components of vehicles,vessels and crafts for land, sea, and aviation, etc.

The composite material can be a concentric gradient layer structurearound a center particle. The center particle can be a solid particle, ahollow particle or a core-shell particle. The center particle can be theinner layer of the concentric layer structure. An outermost layer or aninnermost layer of the concentric layer structure can include particlesof a largest particle size. The layers in a concentric layer structurecan include mono-dispersed layers and/or multi-particle layers asgenerally discussed above. Multiple concentric gradient layer structurescan be configured as a coating applied to a substrate or as aself-supporting article. The concentric gradient layer structure can beattached to and/or applied onto a substrate.

The composite material can be configured such that a compression wavepropagating in the gradient layer structure is distorted. An amplitudeof a compression wave propagating in the composite material can bereduced. The composite material can be configured such that an impactenergy of a compression wave propagating on the gradient layer structureis partially absorbed. The composite material can be configured suchthat after reflection of a shock wave a combined shock wave is reducedin destructive power. The composite material can be configured tomitigate and/or remediate a shock wave. The composite material can beconfigured such that when impacted by a shock wave, particles ofneighboring layers interact thereby inducing primarily a lateralmomentum transfer due to, e.g., a change in the number in contactpoints.

The multilayer composite material can further include a core-shellparticle layer of core-shell particles having a shell surrounding a corematerial. For example, the gradient layer structure can include such acore-shell particle layer or core-shell particle. The core-shellparticle layer can include one or more sub-layers of core-shellparticles.

The shells can be configured to release core material when impacted by aneighboring particle of the composite material, e.g., caused by theimpact of a compression wave.

At least one particle can contain a polymeric material such asurethanes, vinyls, epoxies, phenolics, styrenes, and esters.

At least one particle can contain on or more of ionomers, polymers,polymerizable monomers, resins, and cyclodextrins

At least one particle can contain a fire suppressant of a groupconsisting of carbonate, bicarbonate or halide salts, telomer basedmaterials that incorporate fluorinated materials, halocarbons,hydrofluorocarbons, hydroxides, hydrates, and polybrominated materials.

At least one particle can contain an agent material for generating afoam, e.g., a polymer foam based on, e.g., urethans, and styrenes.

At least one particle can contain a medically active material such asantibiotics and other medicine for infection, disinfectants, burn reliefagents, materials used for medical triage treatment andbiological/radioactive mitigating and/or remediative materials.

At least one particle can be a core-shell material and a material of thecore, when released, is selected to react with at least one of anothercore material, a shell material, an intermediary material, and thematerial of neighboring particles.

Various particles and/or core-shell particles can be configured toprovide a staggered chemical reaction, e.g., when impacted by acompression wave.

At least one of the particles can include a radio frequency (RF)shielding material, such as, for example, copper or nickel, cermet, andcopper or nickel alloys.

At least one of the core-shell particles can include a shell materialcontaining a polymeric material such as urethanes, vinyls, epoxies,phenolics, styrenes, and esters. The shell material can further includeone or more of ionomers, polymers, polymerizable monomers, resins, andcyclodextrins.

At least one of the core-shell particles can include a core materialcontaining a fire suppressant such as carbonate, bicarbonate or halidesalts, telomer based materials that incorporate fluorinated materials,halocarbons, hydrofluorocarbons, hydroxides, hydrates, andpolybrominated materials.

At least one of the core-shell particles can include a core materialcontaining an agent material such as a polymer foam, urethan, andstyrenes.

At least one of the core-shell particles can include a core materialcontaining a medically active material such as antibiotics and othermedicine for infection, disinfectant, burn relief agents, materials usedfor medical triage treatment, and biological/radioactive remediativematerials.

At least one of the core-shell particles can include a core containing amaterial, when released, to react with at least one of another corematerial, a shell material, an intermediary material, and the materialof neighboring particles.

At least one of the core-shell particles can include a core containing amaterial configured, when released, to mitigate and/or remediate asecondary blast effect of an explosion.

A core-shell particle can be a free and unrestricted in its movement.

The shells can be configured to provide the core material at apredefined physical condition. For example, the shell can be configuredto rupture at a threshold pressure derived from the pressureaccompanying, e.g., shock waves generated by a blast. The shell can befurther configured to rupture at a specific pressure caused by the shockwave.

The core-shell particle layer can further include an intermediarymaterial configured to evaporate during impact of the blast wave therebyproviding unrestricted movement of the core-shell particles.

A position of a core-shell particle layer in a composite material candefine a minimum strength of an impacting compression wave that isrequired to initiate the release of the core material.

Moreover, core-shell particles can have core material that change thephysical properties of the core-shell particle compared to a solidparticle. For example, gas-filled particles (herein referred to ashollow particles) can be more deformable than solid particles andthereby contribute differently to, e.g., the absorption of shock waves.The structure of the core-shell particles (shell thickness and/or typeof shell material and core material) may be selected to provide elasticdeformable particles or inelastic (and therefore breakable) particlesfor respective stress situations such as impacting shock waves.

In a transportation device, the composite material can be configured asat least one of a coating, a film, and a panel attached, e.g., to anexterior surface. Moreover, the composite material can be providedwithin a cavity of a structural component of the transportation device.

The composite material can be configured to reduce a compression wave toprovide a predefined threshold pressure at the core-shell particlelayer.

In some embodiments, the composite material is capable of absorbing animpact of a shock wave that, for example, is produced by an explosion orcaused during operation of a device. In addition, or alternatively, insome embodiments, the composite material is capable of mitigating and/orremediating one or more secondary blast effects resulting from theexplosion.

In some embodiments, the composite material is suitable for use inapplications that can benefit from a material capable of interactingwith or responding to changes in its surrounding environment. Theinteraction and/or response can be designed to be performed in acontrolled and/or predetermined manner. Exemplary changes in theenvironment include changes based on variations of mechanical stress(caused by mechanical load, torsional strain, vibrations etc.),pressure, temperature, moisture, pH-value, electric or magnetic fields,and the like.

Examples of applications can include structural materials, ceramics,textiles and antiballistic and anti-shockwave materials. The field ofapplications can be in civil engineering, aerospace, automotiveapplications, military, energy and related infrastructure, electronics,sensors and actuators, lubricants, medical applications, and catalysis.

In particular, one can release catalysts upon actuation of the compositematerial, which can then be used to catalyze materials in variousapplications. For example, upon impact related fracture of liners orpiping or containers, one can design the composite material to releasematerials that contain spills and clean up via catalysis. Applicationsinclude petroleum/oil based piping systems, chemical containers, andrefining operations.

Additional applications can include shock wave and/or impact protectionof electronic equipment, impact protection in automotive applicationsand sports equipment, coatings and claddings for buildings or oilpipelines (and the like). Oil pipelines, for example, are confrontedwith compression waves due to opening and closing of valves. To mitigateand/or remediate, for example, fire or leaking from an intentionallydestroyed oil pipeline, the inside surface or the outside surface of theoil pipeline, or both, can further be provided with fire mitigatinglayers. This can be done alternatively or additionally to compressionwave absorbing coating or cladding on the inner or outer surface of thepipeline.

In some embodiments, the composite material is capable of reacting toand/or interacting with one or more stimuli existing in a blast zoneenvironment. For example, in some embodiments the material can absorb atleast a portion of an initial blast impact and/or pre-over pressure airwave resulting from an explosion. In addition, or alternatively, thematerial can be designed to mitigate and/or remediate one or morerelated blast effects resulting from the blast impact itself. Thus, someembodiments can provide a novel material that through intelligent designof the material systems can not only reduce blast impact with greaterefficiency and efficacy but that can also mitigate and/or remediate oneor more secondary blast effects.

In some embodiments, the composite material can provide bomb blastmitigation and/or remediation by reducing the reflective value of thebomb blast by absorption of the bomb blast energy. In some embodiments,the primary mitigating and/or remediating process can be by absorptionof the bomb blast shock wave. In some embodiments, the mitigating and/orremediating process can be by absorption of the pre-over pressure airwave that precedes the shock wave. Absorption of the shock wave and/orthe pre-over pressure wave can occur through one or more mechanisms,including, for example, momentum transfer, destruction of the spatialsymmetry of, e.g., the blast wave, plastic deformation, rupture ofparticles, e.g. filled and unfilled core-shell particles, hollowparticles, restitution, and interparticle/interlayer shear.

In some embodiments, the composite material can provide a novel platformfrom which a wide variety of blast effects can be mitigated and/orremediated. For example, in a core-shell material the absorbed energycan be utilized to rupture, e.g., microcapsules to introduce a series orselection of core materials or material systems into the blastenvironment and to thus mitigate and/or remediate the blast effects. Insome embodiments, the composite material can provide a relatively lightweight material that can be applied to pre-existing structures orsystems with no deleterious effects on the performance attributes of thepre-exiting structure or system.

In some embodiments, the composite material can offer proactivemitigation by, for example, comprising RF shielding materials that canimpede and thereby reduce the possibility of a remote detonation.Furthermore, destructive phenomena can also be addressed through thecomposite material including remediative solutions to chemical,biological, radioactive, optical, sonic, mechanical failure, andelectromagnetic effects.

In some embodiments, textiles, materials of construction, and smart andthin film applications can benefit from the composite material as amultifunctional user defined “smart” material. Exemplary textileapplications can include textiles for use in firefighting, lawenforcement, military, defense, sports, and fashion. In someembodiments, composite material can be provided in a form such as acloth or film suitable for forming uniforms, helmets and head gear, orbeing applied thereto when using them as a substrate that exhibit thebeneficial effect of reacting to environmental changes in apredetermined manner. Exemplary uniforms, helmets, and head gear caninclude those protective uniforms, helmets, and head gear worn byfireman, law enforcement personnel, and military and/or combat personneland sports teams and those participating in sports activities.

Examples of composite material applications include further materialsystems which are designed to utilize latent or introduced energy toperform a multiplicity of internally predictable actions utilizingenergy from the system as an energy source for inducing said actions.Applications also exist which utilize the conversion of impact energy(from physical, optical, acoustic, compression etc.) to perform avariety of functions including energy conversion and utilization,actuation of sensors, signals and chemical reactions in multi-stepsystems which can, in concert, perform a variety of complex user definedfunctions.

Some embodiments provide “bomb proof”, impact or smart materialapplications. Examples of bomb proof applications include receptaclesand liners (waste receptacles and bags etc.), construction (buildingsand their facades, bridges and their structural members, pipes andpipelines (for fossil fuels, conduits, utilities), automotive (doorpanels, bumpers, dashboards, windshields and windows, undercarriages androofs), aerospace (interior/exterior of planes, satellites,helicopters), and high tech (computer/hardware casings, cableprotection).

In some embodiments, the composite material can be used in connectionwith military equipment, structures, vehicles, vessels and crafts forland, sea, and airborne forces to include armored and armored vehicles,aircraft, (which includes helicopters and unmanned drones), and nauticalvessels such as submarines, ships, boats and the like.

For military and civilian uses, the composite material can be applied asan exterior coaling, film, and/or as a panel to pre-existing equipmentor, alternatively, can be utilized as a composite material for formingstructural components of the military vehicle, aircraft, or nauticalvessel. Still further, the composite material can also be utilized toprovide shielding of electromagnetic radiation (RF etc.) in any of theabove-mentioned contemplated applications.

In some embodiments, the color changing sensor material of the compositematerial can be contained in at least one of the microscale particles,the core-shell particles, an intermediary material, a material of abinding layer, and a material of a binding film of the compositematerial.

In some embodiments, the color changing sensor material of a compositematerial can be configured to change color when exposed to at least oneof gaseous explosive materials, material components of explosives,materials emitted from an explosive material, vapor of an explosivematerial, chemical components outgassed from an explosive material, andchemical components of an explosive material. The color changing sensormaterial can be further configured to change color when exposed tovapors signaling the presence of explosive material; either theexplosive material itself or a chemical component of a manufacturedexplosive.

In some embodiments, the color changing sensor material of a compositematerial can be configured to change color when exposed to a compressionwave.

In some embodiments, the color changing sensor material of a compositematerial can be configured to change color when exposed to the force ofan impact of sufficient magnitude to cause blunt force trauma, mTBIand/or TBI.

In some embodiments, the core-shell particles in the composite materialcan include a core containing a material, which when released, reactswith at least one of another core material, a shell material, anintermediary material, and the material of neighboring particles.

This may cause a change in the color of one or more of those materials.Thereby, a change in the color of the surfaces with which the sensormaterial makes contact can occur. In some embodiments, the released corematerial modifies the consistency (e.g., aggregate state) of one or moreof the, e.g., shell material, intermediary material, and material ofneighboring particles. Those modified materials can have features thatmark (e.g., color) a contacting material (e.g., hair in case of usingthe composite material within a helmet embodiment). In some embodimentsof the multilayer composite material, the first substrate can include apolar material to increase the adhesion of the microscale particles ofthe layer structure being in contact with the first substrate.

In some embodiments, the gradient layer structure can include a seriesof gradients having the same direction.

In some embodiments, the gradient layer structure can include a seriesof gradients having varying directions.

In some embodiments, the core-shell particles can form a layer of thegradient layer structure.

The core-shell particles can have a size at the upper end of the rangeof particle sizes.

The multilayer composite material can further include a second substrateat the second face of the layer structure. The first substrate, thelayer structure, and the second substrate can be at least partiallytransparent.

Certain implementations may have one or more of the followingadvantages. Some implementations can absorb the compression of a bombblast rather than containing bomb blast within a receptacle. Absorptionis more effective as it reduces the destructive power of a bomb ratherthan contains the destructive power. Some implementations can offerremediation of blast effects. Some implementations can offer a largeselection of other functions in situ. Functions can be actuated, forexample, in real time by the impinging compression wave. The actuationcan be performed at any time. Some implementations can be applied toexisting objects and structures without changing initial form orfunction. Some implementations can be easily augmented to accommodatecase specific responses and can be designed to offer user definedproperties. Some implementations can be tunable to offer user definedcomplex and multifunctional performance characteristics. Someimplementations can offer a novel material design approach capable ofengineering directly into the material a predictable series of responsesto an external stimulus, thereby generating a smart material. Someimplementations can enable utilizing and combining the properties ofindividual materials in concert or in series. The details of one or moreembodiments of the invention are set forth in the accompanying drawingsand the description below. Other features, objects, and advantages willbe apparent from the description and drawings, and from the claims.

Additional features, advantages, and embodiments of the invention areset forth or apparent from consideration of the following detaileddescription, drawings and claims. Moreover, it is to be understood thatboth the foregoing summary of the invention and the following detaileddescription are exemplary and intended to provide further explanationwithout limiting the scope of the invention as claimed.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS

FIG. 1 is a schematic cross sectional view of a first composite materialwith a gradient layer structure having a decreasing particle size inimpact direction.

FIG. 2 is a schematic cross sectional view of a second compositematerial with a gradient layer structure having an increasing particlesize in impact direction.

FIG. 3 is a schematic cross sectional view of a third composite materialwith a plurality of gradient layers structures as shown in FIG. 1.

FIG. 4 is a schematic cross sectional view of a fourth compositematerial with a plurality of gradient layers structures as shown in FIG.2.

FIG. 5 is a schematic cross sectional view of a fifth composite materialwith a plurality of gradient layers structures as shown in FIGS. 1 and2.

FIG. 6 is a schematic cross sectional view of a sixth composite materialwith a plurality of concentric particle layers.

FIG. 7 is a schematic illustration of blast environment.

FIG. 8 is a graph of a temporal pressure development in a shock wave.

FIG. 9 is a schematic illustration of a reflection of a shock wave at aseventh composite material.

FIG. 10 is a schematic illustration of momentum transfer in a gradientlayer structure.

FIG. 11 is schematic illustration of an exemplary core-shell particle.

FIG. 12 is a schematic cross sectional view of a planar layer structureof mono-dispersed core-shell particles on a substrate.

FIG. 13 is a schematic cross sectional view of a planar gradient layerstructure including a core-shell particle layer.

FIG. 14 is a schematic cross sectional view of a concentric gradientlayer structure surrounding a core-shell particle.

FIG. 15 is a schematic cross sectional view of a container coated with acomposite material as shown in FIG. 1.

FIG. 16 is a schematic cross sectional view of a fiber coated with acomposite material as shown in FIG. 1.

FIG. 17 is a schematic cross sectional view of a fiber coated with acomposite material as shown in FIG. 14.

FIG. 18 is a perspective view of a pipeline.

FIG. 19 is a perspective view of a hand held device.

FIG. 20 is a schematic illustration of a compression wave deformation ina gradient layer structure.

FIG. 21 is a cross section through a helmet with helmet liner pads, anda helmet liner.

FIG. 22 is a schematic cross sectional view of an exemplary structure ofmicroscale particles for a helmet liner pad.

FIG. 23 is a schematic representation of a transportation deviceprovided at least partly with a composite material.

FIG. 24 is a schematic cross sectional view of an exemplary wastereceptacle made from a multilayer composite material.

FIG. 25 is a schematic cross sectional view of a composite material witha gradient layer structure illustrating multi-particle layers.

FIG. 26 is a schematic cross sectional view of a composite material witha gradient layer structure illustrating an alternating gradientdirection.

FIG. 27 is a schematic cross sectional view of a composite materialillustrating multi-particle layers with concentric particle layers.

FIG. 28 is a schematic cross sectional view of a composite materialillustrating multi-particle layers with concentric particle layers.

FIG. 29 is a schematic cross sectional view of a composite material withplanar multi-particle layers on a substrate.

FIG. 30 is a schematic cross sectional view of a composite material withplanar multi-particle layers forming a uni-directional gradient.

FIG. 31 is a schematic cross sectional view of a composite material withplanar multi-particle layers forming a gradient with changing direction.

FIG. 32 is a schematic cross sectional view of a composite material withplanar multi-particle layers forming a gradient alternating indirection.

FIG. 33 is a plot of the particle size over the layers of a gradientstructure.

FIG. 34 is a plot of the particle size over the layers of a gradientstructure.

FIG. 35 is a plot of signals of an impact tester for various assemblies.

FIG. 36 is a scanning electron microscope image of a composite material.

FIG. 37 is a scanning electron microscope image of a cross section ofthe composite material of FIG. 36.

FIG. 38 is a scanning electron microscope image of a composite material.

FIG. 39 is a scanning electron microscope image of a cross section ofthe composite material of FIG. 38.

FIG. 40 is a plot of a depth-dependent hardness of a surface of acomposite material.

FIG. 41 is a plot of a depth-dependent hardness of a surface of acomposite material.

FIG. 42 is a schematic representation of a safety glass with a compositematerial in a sandwich structure.

FIGS. 43 to 48 are schematic plots of particle sizes distribution of thelayers of a composite material.

FIGS. 49 to 54 are schematic plots of particle sizes distribution of thelayers of a composite material based on solid and core-shell particles.

FIG. 55 is a schematic cross sectional view of a densely packed particlestructure.

Like reference symbols in the various drawings may indicate likeelements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In some aspect, the invention relates to an engineered compositematerial that is based on a structure of particles with a gradient layerstructure having different particle sizes in neighboring layers and adensely packed particle structure that has essentially no restriction tothe distribution of the particle size over the cross section.

For the gradient layer structure, the layers can be arranged to have a(constant or varying) gradient of the particle sizes, e.g., increasing,decreasing, or alternating particle size.

In contrast, the densely packed particle structure is a non-gradientparticle structure with, for example, particles of a single size only,or particles of two sizes. The particles of the densely packed particlestructure can be arranged in monolayers or layers a few particles thick,thereby forming a densely packed layer structure of the particles. Sucha layered densely packed particle structure can be generated, forexample, layer by layer. In addition, a densely packed particlestructure can also be generated as a bulk, e.g., by drop coating.

A densely packed particle structure is described in more detail, forexample, in PCT patent application, filed on Aug. 11, 2009 asPCT/US2009/053465 and entitled “DENSELY PACKED PARTICLE STRUCTURE” by Z.R. Greenhill, Y. C. Avniel, and J. J. BelBruno, the contents of which ishereby incorporated by reference in its entirety.

Such a gradient layer structure can be capable of absorbing, forexample, the energy of a sports impact, explosion, pressure waves, soundwaves, shock waves, and compression waves. In general, the layers of thecomposite material, e.g., of the gradient layer structure or a layereddensely packed gradient structure, can be mono-dispersed layers ormulti-particle layers, i.e., a layers that have a thickness given by asingle (mono-dispersed layer) or multiple particles (multi particlelayer) being positioned along the direction of the cross-section of thelayer. Within a multi-particle layer, the particle size is essentiallyconstant.

A specific situation occurs for a multi-particle layer within a gradientlayer structure, where the interaction between same size particles takesplace in addition to interaction between different size particles. Thisinteraction is similar to the interaction between particles of thedensely packed particles having the same size. Depending on the numbersof layers, one may consider those multi-particle layers a separate unitof a densely packed particle structure sandwiched between two gradientlayer structures. In general, one can in general consider multi-particlelayer structures of approximately the same thickness, number of layers,or efficiency as, the gradient layer structure to be a densely packedparticle structure. Multi-particle layers of smaller size, number oflayers, or efficiency than the gradient layer structure can beconsidered to be part of the gradient layer structure.

Examples of gradient layer structures and/or densely packed particlestructures are discussed, for example, in connection with FIGS. 1 to 6,9, 13 to 24, 43 to 55. The physical environment generated by a bombblast is discussed below in connection with FIGS. 7 and 8, and apotential explanation for the effect of the invention is discussed inconnection with FIGS. 9 and 10. In various descriptions herein, a bombblast is described; however, without being constrained by a theory,Applicant believes a similar physical environment would be created by asports impact and other related events. The presented gradient layerstructures and/or densely packed particle structures can provide anincreased lateral momentum and energy transfer during propagation of anincident wave. For example, when gradient layer structure and/or adensely packed particle structures are subjected to the impact of asports impact or blast, the compression wave from the blast travelsacross the structures, and it is assumed that the compression wave isincreasingly deflected in different directions by, e.g., the alternatingamount of contact points within neighboring layers.

In such multilayer composite materials, the particle size can range fromabout 1 nm to several millimeters, for example, from 150 nm to 1 mm. Thematerial of the particles can comprise, e.g., (porous) silica; aluminumhydroxide; polymeric materials; metal spheres, and ceramics. As shownspecifically in FIGS. 3 to 5, a composite material can include severallayer structures with identical or reversed direction of the gradientand sections of no gradient. The layers can be planar or have a specificshape. Moreover, the structures can be applied to a substrate having aspecific shape, see FIG. 3. Alternatively, the structures can beconcentric as for example described in connection with FIG. 6.

While most of the drawings shown herein illustrate a layer just by astring of single particles, any of the layers shown herein can ingeneral be a layer of mono-dispersed particles or a multi-particle layerhaving more than one sub-layer (a sub-layer itself being, for example, adense mono-dispersed particle layer). Examples are described inconnection with FIGS. 25 to 32, which show composite materials thatinclude gradient layer and densely packed particle structures based onlayers of mono-dispersed particles and multi-particle layers. In thedrawings, densely packed particle structures are often illustrated as asingle layer but are in general multilayer structures or non-layeredstructures having the thickness of the size of several particles.

In some aspects, a composite material includes core-shell particleshaving a core surrounded by a shell. The core can be partly orcompletely filled with solid, liquid, gaseous, and/or gel-like material.Depending on the specific application, the shell materials of thecore-shell particles can be configured to be pliable during interactionwith a compression wave, thereby attenuating the compression wave inaddition to any structural attenuation effect of several particles. Theattenuation effect of a core-shell particle depends on the material ofthe shell (e.g., its elasticity) and the physical properties of the corematerial. A gas filling of a so called hollow core-shell particle (or apartly with a solid filled core-shell particle) will itself essentiallynot contribute to the physical properties of the core-shell particle,while a complete solid or liquid filling can modify the physicalproperties of the core-shell particle.

In some aspects, a composite material includes core-shell particles suchas filled microspheres, see FIG. 11 that are “filled” with one or moreapplication specific materials within one or more core-shell particles.Depending on the specific application, the shell materials of thecore-shell particles can be configured such that given a specificphysical pressure, the core material is released. In exemplaryembodiments, the composite material can include a monolayer ofmono-dispersed core-shell particles or a layer having a thickness ofmultiple core-shell particles (multi-core-shell particle layer with morethan one sub-layer). Exemplary materials for the core can include forfire suppression materials such as potassium bicarbonate, aluminumand/or magnesium hydroxide; for energy absorption porous silica, silica,and/or Perlite; and for RF shielding copper, and/or nickel.

In some applications, the physical properties of core-shell particlesare essentially determined by the shell and the filling (core-material)is, for example, a gas, a gas-liquid mixture, or a gas-gel mixture, or agas-solid mixture, which does not or only to some extent contribute tothe interaction with, for example, a pressure wave.

Moreover, in some aspects, the core-shell particle layer can be combinedwith a gradient layer structure as discussed, for example, in connectionwith FIGS. 13, 14, 17, 22, and 24. In general, throughout the compositematerial one or more mono-dispersed layer of core-shell particles and/orone or more multi-core-shell particle layers can be provided.

In various applications, the composite materials based on gradient layerstructure and densely packed particle structure with or withoutcore-shell particles can be applied to devices such as containers asshown in FIGS. 15 and 24 as examples for waste receptacles. Thecomposite material can further applied to fibers and used in connectionwith textiles as discussed in connection with FIGS. 16 and 17. Exemplarytextile applications can include textiles for use in firefighting, lawenforcement, military, defense, sports, and fashion. Such cloth or filmcan be suitable for forming uniforms, helmets, helmet liners, helmetliner pads etc. that exhibit the beneficial effect of reacting toenvironmental changes in a predetermined manner. Specific examples caninclude inner liners for uniforms or jackets that are either attachableor fused into the cloth.

Additional applications can involve the suppression of compression waves(including shock waves) in pipes. Compression waves are, for example,generated through valve operation in oil pipelines as discussed inconnection with FIG. 18. The composite material can further be appliedto surfaces that require impact resistance. Examples include housing ofhand held devices, helmets, vehicles or components thereof, as discussedin connection with FIGS. 19, 21 to 24. The composite material in thoseapplications can be applied as a coating (e.g. film) or provided as aliner. The composite material can further be used in connection withcushions, for example, the helmet pads shown in FIG. 21. Additionalapplications can involve the suppression of compression waves to makewall structures or windows safer.

In general, for composite material in applications, which require aminimum transparency, the material and the size of the particles can beselected appropriately. In general, particle sizes below about 200 nmcan enhance the transparency. For example, 30-50 layers of silicaparticles of 200 nm size are transparent.

The composite material can be generally comprised of a plurality ofadjacent layers whereby each layer is comprised by a plurality ofparticles having a predetermined median particle size diameter. Ingradient layer structures, the predetermined median particle size ofeach adjacent layer (be it a layer of mono-dispersed particles or amulti-particle layer), when viewed in cross section, forms a particlesize gradient such that median particle size of each layer sequentiallydecreases (or increases) across the cross section of the material. Theparticle size gradient is accompanied by an inverse “gradient” in theamount of contact points per unit of area. For example, a decreasingparticle size within the gradient layer structure results in an increaseof particle surface contact points per unit of area because moreparticles interact in each adjacent layer. Similarly, an increasingparticle size within the gradient layer structure results in a decreaseof particle surface contact points per unit of area because lessparticles interact in each adjacent layer. A gradient layer structurecan, in general, include changes in the gradient, i.e., in the steepnessof the change of the particle size and the direction of the change inthe particle size.

In contrast to the gradient layer structure, densely packed structuresmay have a constant number of particles and therefore, amount of contactpoints. In general, allowing random particles size distributions, alsothe number of particles and contact points changes randomly. Inpractice, the random particle size distribution is, however, restrictedby the particles provided and controlled during the manufacturing.

The size of the particles forming the surface of the composite materialor the side of the composite material that interacts with an incomingdistortion can additionally influence the physical properties of thecomposite material. The influence on the surface hardness is discussedbelow, for example, in connection with Example 7.

Herein various aspects are discussed for layer structures, even thoughsimilar considerations are also applicable for a non-layered denselypacked particle structures.

The plurality of adjacent layers are configured such that the proximityof the particles within the various layers and the proximity ofparticles from one adjacent layer to another adjacent layer aresufficiently close to one another to allow a transfer, dissipation,and/or conversion of energy to take place when the gradient layerstructure is subjected to the impact energy from, for example, a sportsimpact or a blast. Specifically, a momentum transfer response onlyoccurs when the particles are touching and compressed. Once the contactbetween particles is not possible, the particles can become anamalgamation of independent systems which in themselves interact as amultitude of systems.

FIG. 1 shows a schematic cross-sectional view of an exemplary compositematerial 100. The direction of an impact, e.g., the compression wave ofa sports impact or blast, is indicated through arrow 105 and is directedtoward a surface of a composite material 100. The composite material 100includes a plurality of adjacent layers 110-170. Each of the layers110-170 of the material includes particles p1-p7 having a predeterminedmedian particle size dp1-dp7, respectively. The relative particle sizedistribution with respect to the median particle size dp1-dp7 of theparticles p1-p7 within any given layer 110-170 is small. For example,the coefficient of variation is below 20%, or below 10%, or even below5%.

With respect to the gradient structure, each layer of the compositematerial 100 can be distinguished from the adjacent layer or layers bythe difference in particle sizes contained therein. Additionally, withineach of the layers 110-170 of FIG. 1, particle surface contact pointscp1-cp7 between particles of each of the layers 110-170 are indicated.As can be easily seen, the smaller the particle the more contact pointsper unit of area.

In FIG. 1, the particle sizes of each adjacent layer form a particlesize gradient and satisfy the relationship dp1>dp2>dp3>dp4>dp5>dp6>dp7.It should be understood that the specific median particle sizes selectedfor a given layer of the material are not as critical as long as adesired particle size gradient is provided.

The gradient can be expressed as the change in size of the particlediameters populating individual layers. For example, the particlediameters can shrink (or increase) progressively by a factor spanningthe range of 5% and 50%. The shrinking or increasing can be linear ornon-linear.

In direction of a decreasing median particle size, the median particlesize of the adjacent layers 110-170 can be chosen such that number ofparticle surface contact points cp1-cp7 per unit area increases at leastby one. For example, if one of the layers 110-170 has n particle surfacecontact points then the neighboring layer having a smaller particles hasat least n+1 particle surface contact points per unit area. Accordingly,the number of particle surface contact points fulfills the relation:cp7>cp6>cp5>cp4>cp3>cp2>cp1.

Microscale particles (e.g. sub-millimeter size particles) can be used tomanufacture the composite material and the selection of the size, atleast in part, is dependent upon the desired end use application for thecomposite material. For example, the particle sizes can be less thanabout 1,000 μm in size, less than about 500 μm, less than about 250 μm,or even less than about 125 μm. Particle size down to the singlenanometer scale can be applied.

In case of the composite material 100 of FIG. 1, the particles of layer110 can have a relative median particle size of about 150 μm, theparticles of layer 120 can have a relative median particle size of about75 μm, the particles of layer 130 can have a relative median particlesize of about 40 μm, the particles of layer 140 can have a relativemedian particle size of about 10 μm, the particles of layer 150 can havea relative median particle size of about 2 μm, the particles of layer160 can have a relative median particle size value of 0.75 μm and theparticles of layer 170 can have a relative median particle size value of0.15 μm.

The example of FIG. 1 has seven layers. However, it should also beunderstood that the plurality of layers can comprise less or morelayers, for example three or more layers. Examples for the number oflayers in a composite material having a gradient in the particle sizecan include less than seven layers (e.g., two, three, four, five, six),or more layers (e.g. at least ten, twenty, thirty, forty layers). Table1 shows example layer structures for a gradient of 5% to a gradient of50% starting at a maximum particle size of 40 μm and having up to 40layers within a gradient layer structure. The indicated median particlesizes decrease layer by layer 5%, 10%, . . . 50%. For a gradient of 20%,two layer structures are shown having 20 or 28 layers. Example polymericparticles can include monodisperse polystyrene microspheres andPolybead® Hollow Microspheres. Additional particles and particlematerials are discussed below. Although the foregoing description isdirected to the preferred embodiments of the invention, it is noted thatother variations and modifications will be apparent to those skilled inthe art, and may be made without departing from the spirit or scope ofthe invention. Moreover, features described in connection with oneembodiment of the invention may be used in conjunction with otherembodiments, even if not explicitly stated above.

TABLE 1 Gradient 5% 10% 20% 20% 25% 40% 50% Layer 1 40.00 40.00 40.0040.00 40.00 40.00 40.00 Layer 2 38.00 36.00 32.00 32.00 30.00 24.0020.00 Layer 3 36.10 32.40 25.60 25.60 22.50 14.40 10.00 Layer 4 34.3029.16 20.48 20.48 16.88 8.64 5.00 Layer 5 32.58 26.24 16.38 16.38 12.665.18 2.50 Layer 6 30.95 23.62 13.11 13.11 9.49 3.11 1.25 Layer 7 29.4021.26 10.49 10.49 7.12 1.87 0.63 Layer 8 27.93 19.13 8.39 8.39 5.34 1.120.31 Layer 9 26.54 17.22 6.71 6.71 4.00 0.67 0.16 Layer 10 25.21 15.505.37 5.37 3.00 0.40 0.08 Layer 11 23.95 13.95 4.29 4.29 2.25 0.24 Layer12 22.75 12.55 3.44 3.44 1.69 0.15 Layer 13 21.61 11.30 2.75 2.75 1.270.09 Layer 14 20.53 10.17 2.20 2.20 0.95 Layer 15 19.51 9.15 1.76 1.760.71 Layer 16 18.53 8.24 1.41 1.41 0.53 Layer 17 17.61 7.41 1.13 1.130.40 Layer 18 16.72 6.67 0.90 0.90 0.30 Layer 19 15.89 6.00 0.72 0.720.23 Layer 20 15.09 5.40 0.58 0.58 0.17 Layer 21 14.34 4.86 0.46 0.13Layer 22 13.62 4.38 0.37 0.10 Layer 23 12.94 3.94 0.30 Layer 24 12.293.55 0.24 Layer 25 11.68 3.19 0.19 Layer 26 11.10 2.87 0.15 Layer 2710.54 2.58 0.12 Layer 28 10.01 2.33 0.10 Layer 29 9.51 2.09 Layer 309.04 1.88 Layer 31 8.59 1.70 Layer 32 8.16 1.53 Layer 33 7.75 1.37 Layer34 7.36 1.24 Layer 35 6.99 1.11 Layer 36 6.64 1.00 Layer 37 6.31 0.90Layer 38 6.00 0.81 Layer 39 5.70 0.73 Layer 40 5.41 0.66

In Table 1, a constant gradient of 5% is given. However, one couldalternatively vary the gradient. For example, a gradient layer structurecan include the layers 1 to 7 with a gradient of 25%, followed by layers35 to 40 with a gradient of 5%. Additionally, that gradient layerstructure can include layers 11 to 28 with a gradient of 25%.

Additionally, a composite material can have a layer structure thatincludes a series of repeating layer sequences wherein the order oflayers within a layer sequence can be inverted and/or the layers of asequence can be modified.

For example, as shown in FIG. 1, any one of the layers 110-170 caninclude a mono-dispersed layer of particles p1-p7 and thus has athickness approximately equal to the median particle size diameter ofthe particles p1-p7 within that layer 110-170, respectively. Then,composite material 100 would be a pure gradient layer structure.Alternatively, any one or more layers can also be comprised of aplurality of sub-layers of the particles forming a multi-particle layer.Then, the thickness of a given layer can optionally be greater than themedian particle diameter size of the particles within a given layer ofthe system. Specifically, layers with smaller particles can include, forexample, more than one particle, e.g., up to 20 particles.

Any of the layers 110-170 can, in principle, be a multi-particle layerand therefore be considered a densely packed particle structure. Forexample, the largest particles of layer 100 can include 10, 20, 30, 40,or 50 layer of the same size. A corresponding particle size distributionis shown in FIG. 43.

Additionally (or alternatively), layer 170 of the smallest particles canbe formed as a densely packed particle structure. A correspondingparticle size distribution is shown in FIG. 44.

Alternatively (or additionally), one of the inner layers, e.g., layer140 can be formed as a densely packed particle structure. Acorresponding particle size distribution is shown in FIG. 45.

As further shown in FIG. 1, the energy from a sports impact or blastimpact 105 is directed initially toward the first layer 110 which iscomprised of a plurality of particles having the largest median particlesizes. Thus, the energy of the impact will then propagate though thematerial in the direction of largest particle size to smallest particlesize, i.e., from layer 110 toward layer 170.

As used herein, the terms “nano” and “nanoscale” particles generallyrefer to particles having a size on the scale of nanometers, such as,for example, particles having at least one aspect equal to or less thanabout 100 nm. As used herein, the terms “macro” and “macroscale”particles generally refer to particles larger than nanoscale, preferablyparticles having at least one aspect greater than about 100 nm, or morepreferably particles having at least one aspect greater than about 500nm. As used herein, the terms “meso” and “mesoscale” particles generallyrefer to particles having aspects between nanoscale and macroscalesystems. As used herein, the terms “micro” and “microscale” particlesgenerally refer to particles from the nanoscale to particles having atleast one aspect in the order of thousand micrometers, e.g., in therange of 0.1 nm to 1000 μm.

It should be noted that these sizes and ranges can vary and/or overlapand that therefore the definitions provided herein are intended only toserve as a general guide and not to limit the various embodiments.Nanoscale particles can often exhibit different properties thancorresponding macroscale analogs. Mesoscale particles can often exhibitproperties that can be attributed to both nano and macro systems.

In some embodiments, the composite material includes macroscaleparticles, mesoscale particles, and/or nanoscale particles, such thatthe energy that is dissipated (e.g. frictional energy) can be increased.In some embodiments, combinations of mesoscale and/or nanoscaleparticles achieve application specific mechanical properties and theamount of dissipated energy can be increased.

In a composite material, frictional energy dissipation can be increasedby populating space devoid of macroscale (large) particles withnanoscale and/or mesoscale (small) particles. The choice of particlesize used is a function of a particle size gradient, materialcomposition, and desired properties. The small particles can also beused to adjust the materials' mechanical properties (e.g. mechanicalstrength). In addition, or alternatively, the small particles canintroduce further material systems that can be beneficial upon actuationof the system, e.g., by a bomb blast.

It should also be understood that the composite material is not limitedonly to configurations whereby the layer comprising the largest medianparticle size forms the surface layer and therefore, receives theinitial energy of, e.g., the impact from an impact or a blast. Forexample, as shown in FIG. 2, a composite material 200 can also be formedto comprise the reversed particle size gradient, wherein the first layerto receive the impact energy from the blast is layer 270. According tothis embodiment, the energy of the impact will propagate though thematerial along a direction 205 from the smallest particle size to thelargest particle size, i.e., from layer 270 toward layer 210. In thestructure of FIG. 2, the gradient has the opposite direction to thegradient of FIG. 1 and accordingly, the number of contact pointsdecreases for layers being further away from the surface subjected tothe impact.

In some embodiments, a plurality of the above described materials can bestacked or arranged sequentially one upon the other. For example, asshown in FIG. 3, a composite material sequence 300 includes a pluralityof composite materials 100 (large to small particle size gradient asdiscussed in connection with FIG. 1) can be stacked or arrangedsequentially on top of a substrate 310. Specifically, FIG. 3 shows fivecomposite materials 100. To this end, it should be understood that anydesired number of the layer sequence as shown for the compositematerials 100 can be stacked or arranged in sequence.

Likewise, as shown in FIG. 4, a composite layer sequence 400 includes aplurality of layer sequences as shown for the composite material 200(small to large particle size gradient as discussed in connection withFIG. 2) can be stacked or arranged sequentially. Once again, it shouldbe understood that any desired number of layer sequences can be stackedor arranged in sequence. A larger number of gradient layer structuresand gradient layers can provide self-standing structures, while fewerlayers or gradient layer structures can provide a flexible compositematerial that can be applied to structured surfaces. In FIG. 4, asubstrate is not explicitly shown, thereby indicating a self-standingstructure. However composite layer sequence 400 can alternatively beattached to a substrate, for example at the large particle side.

In some embodiments, and as shown in FIG. 5, a plurality of thecomposite materials 100 and 200 can be stacked or arranged in analternating or staggered arrangement to form a composite material 500 sothat the interface of two adjacent materials 100 and 200 can compriseeither a divergence or a convergence of particle size gradients. Onceagain, it should be understood that according to this embodiment, anydesired number of the composite materials 100 and 200 can again bestacked or arranged in the manner as described. While in FIG. 5 largerparticles form the surface, one can alternatively form the gradientstructure such that the smallest or medium size particles form thesurface (see, e.g., FIG. 31). Opposing surfaces of a composite materialcan also be provided with different size particles.

As illustrated in FIGS. 1 to 5, the composite material can be providedas a plurality of substantially parallel or sequential layers which can,for example, be attached, applied or deposited sequentially onto asubstrate. However, in some embodiments and as shown in FIG. 6, theplurality of layers can be oriented concentrically, thereby forming aconcentrically layered particle 600. The concentrically layered particle600 includes a central particle 610 that is surrounded by a plurality ofconcentric layers, only two layers 620 and 630 are shown but many morecould be applied. The concentric layers are each comprised of particlesof decreasing size as the layers extend farther from the central or coreparticle 610. As exemplified in FIG. 6, the central particle 610 has apredetermined particle size dp1. First outer concentric layer 620 iscomprised of a plurality of particles having a median particle size dp2that is less than the dp1. The second outer concentric layer 630 iscomprised of a plurality of particles having a median particle size dp3that is less than dp2. Once again, although this embodiment has beenexemplified in FIG. 6 as having the central particle 610 surrounded bytwo concentric particle layers 620 and 630, it should be understood thatany number of concentric particle layers can be applied and a centralparticle is not required and could be replaced by free space or a fewcontacting inner particles.

As discussed above for the embodiments of FIGS. 1-5, the direction ofthe gradient can be reversed or different types and/or directions ofgradients can be used within a gradient structure.

Similarly, in the above discussion, one or more layers (except the coreparticle 610) can be the densely packed particle system. In a respectivediscussion of FIGS. 43 to 54, consider the layer number extends then inradial direction, while in planar embodiments the layer number extendsalong the cut through the layer structure.

It should be appreciated that one advantage of the concentricallylayered particles 600 is its potential ease of large scale application.In particular, a plurality of the individual concentrically layeredparticles 600 can be suspended in a medium and subsequently applied ontoa desired substrate. This technique can thus enable the generation of aproduct with a desired energy absorption effect that is based on asingle application of concentrically layered particles 600, rather thanon a plurality of successive applications, to provide the differentlayers such as, e.g., the layers 110-170 of composite material 100.

The individual layers which are populated by the different sizedparticles have a number of distinct attributes. In some embodiments, thelayer thickness can at least for the layers of larger particles be asclose as possible to the particle diameter, while for layers of smallerparticles multi-particle layers may be applied having a thickness ofe.g., 2-20, 5-15, and 7-12 particles, e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11,or 12 particles. As discussed above, one can in general considermulti-particle layer structures of approximately the same thickness,number of layers, or efficiency as the gradient layer structure to be adensely packed particle structure. Multi-particle layers of smallersize, number of layers, or efficiency than the gradient layer structurecan be considered to be part of the gradient layer structure.

The particles within the layers can be in a densely packed structure,thereby providing a high number of contact points between the particlesor particles after being moved only for a short distance (e.g. less thanthe particle size).

The composite material can be used to mitigate and/or remediate thedamage of high intensity compression waves, such as shock waves causedby a sports impact, an explosion, etc. While not wishing to be bound bytheory, several mechanisms are presented which are assumed to beresponsible for the mitigating features of the composite material.Explosions are described, but other impacts, such as sports impacts maybehave in similar manners when interacting with embodiments of thepresent invention.

When an explosive device detonates, it can impact the surroundingenvironment, in particular the blast zone, in various distinct ways. Inparticular, as shown in FIG. 7, the explosion of a bomb 10 results in aninitial bomb blast with a shock wave 20 of high pressure, i.e., acompression wave, followed by a low pressure zone 30.

The bomb blast can be viewed as a three dimensional wave emanating fromthe origin of the bomb blast. The leading edge of the blast waveexhibits a nearly discontinuous increase in pressure, density andtemperature. The transmission of a bomb blast through a medium isinherently a nonlinear process and can be described by nonlinearequations of motion. Considering an ideal bomb blast produced from aspherical and symmetric source and propagated in a still and homogenousmedium, the resulting bomb blast will also be perfectly spherical andtherefore the characteristics of the blast wave are functions of adistance R from the center of the source and the time to travel adistance t.

As shown in FIG. 8, the pressure changes across the shock wave 20 andthe low pressure zone 30. Prior to the impact of the shock wave 20, at agiven point, the pressure is equal to the ambient pressure p0. At a timeto that coincides with the arrival of the shock front, the pressurerises discontinuously to a peak pressure of p0+Ps+ (over-pressure 800 inthe shock wave zone 20). The pressure then decays to ambient pressure ina total time ta+T′, drops to a reduced pressure p0−P− (under-pressure810 in the low pressure zone 30), and eventually returns to ambientpressure p0 in a total time ta+T++T−.

When compression of a medium exceeds the ability of thermal motion todissipate the energy, the over-pressure 800 occurs. The peak pressurep0+Ps+ of the over-pressure 800 can be correlated to the damage producedfrom the explosion and is considered a primary source of bomb relatedinjuries. Through increasing the over-pressure 800, the reflection of ablast wave from a surface can magnify its destructive power severaltimes. For example, when the shock wave 20 impacts upon a solid surface,it can reflect off the surface and increasing up to nine times indestructive power. Thus, being able to control the reflection of theblast wave based, for example, on coatings of the composite material canallow reducing the destructive power.

The explosion can further result in the formation of a fire ball 40,which trails the blast. Additional secondary blast effects can presentdistinct threats to life, limb, and property. For example, radioactivematerials can cause significant health issues to victims initiallyimpacted by a detonation, along with individuals who later come intocontact with blast victims and/or materials exposed to radioactivematerials. Chemical agents, such as, for example, nerve, blister, blood,and choking agents, can be released into the environment causingpoisoning in people and the environment. Biological materials and/orbiological toxins (e.g., Bacillus anthracis), viral agents (e.g., SARSand smallpox), biological toxins (e.g., ricin), or other types ofbiological materials (e.g., Q fever) can incapacitate, kill, orcontaminate the environment.

In the case of electromagnetic weaponry, humans can suffer tissuedamage, and electronic systems can suffer irreversible damage. Sonicblasts can rupture living tissue, destroy hydraulic, electronic, andmechanical systems and can propagate large distances from the initialblast source. In addition, other substances can cause a plethora ofdestructive responses by, for example, malicious intent or naturaltendency. Although not shown, another blast effect is caused byaccelerating particulate material and shrapnel that can also result fromthe force of the blast.

As described below in connection with, for example, FIGS. 11-24, anembodiment of a composite material can be configured to mitigate and/orremediate one or several of those secondary blast effects.

While not wishing to be bound by theory, several mechanisms areexplained in connection with FIGS. 9 and 10. As illustrated in FIG. 9,the mechanisms are considered to contribute to the reduction of thedestructive power of a shock wave 910 when reflected from a compositematerial 900 with a gradient layer structure. Exemplary mechanismsinclude energy absorption, wave dispersion, and braking of the wavesymmetry.

While in FIGS. 9 and 10 essentially gradient layers are shown, it isnoted that the densely packed particle structure can be based, forexample, on one or more of the indicated layers. In addition, while mostof the discussion of the densely packed particle structure refers tolayers, similar considerations can most of the time be performed fornon-layered structures.

In FIG. 9, a reflected shock wave 920 is illustrated to have a reducedamplitude corresponding to an energy absorption mechanism duringreflection. The energy absorption can be based on internal friction (dueto shear forces between the layers), inelastic interaction betweenparticles, and/or the breaking of particles or particle shells.

In addition, the reflected shock wave 920 can be stretched in time (asshown), e.g., dispersed due to a modified momentum transfer mechanismbased on the gradient structure and/or densely packed particle structureas discussed in connection with FIG. 10. The propagation of the wave inthe direction of arrow 1005 through a gradient layer structure 1000depends specially and temporally on the momentum transfer between theparticles, e.g., of the various layers of the gradient layer structure1000. As indicated in FIG. 10 through double arrows 1020, momentum canbe transferred between particles of the same layer. A momentum transferbetween particles of neighboring layers is in general not parallel tothe propagation direction of the wave through the composite material.Arrows 1030 indicate the momentum transfer direction between particlesof neighboring layers, which is given through the contact points ofthose particles. Thus, the momentum associated with the impacting wavecan be redirected and then partially absorbed within the layers. Basedon the large number of contact points and momentum transfer events, theincreased particle numbers in the layers with the smaller particles areassumed to contribute to the reduction in energy.

Moreover, as explained in connection with FIG. 20 the symmetry of a wavefront 2000 of, e.g., a wave can be distorted during propagation within acomposite material 2005 along a direction 2010 of propagation. FIG. 20shows a sequence of schematic illustrations of the wave front 2000 atfour positions within the composite material 2005. Four schematicdrawings 2006, 2007, 2008, and 2009 of the composite material 2005illustrate additionally the location of four increasingly distorted wavefronts 2001, 2002, 2003, and 2004. Layers with black spheres correspondto the position of the wave front within the gradient layer structure2005.

As shown in FIG. 20, the incident wave front 2000 is assumed to beessentially a planar wave that is well defined and has a large amplitude(compression wave). In FIG. 20, the magnitude of the amplitude isillustrated by the thickness of the lines representing the wave front.

Within the composite material 2005, the wave front of the compressionwave becomes distorted. Specifically, when interacting with particles ofvarious sizes of the various layers of the gradient layer structure2005, and, in particular, when advancing from one layer to another, theplanar form of the wave front is distorted.

For example, and while not wishing to be bound by theory, at somelocations in the plane of the wave front, the compression wavepropagates slower than at others. For a first layer 2011 of the gradientlayer structure 2005, the upper and lower parts of the wave front 2001are delayed. Thus, in the first layer 2011, the spatial extent of thecompression wave in the direction 2010 of propagation increases to aspreading A.

When the wave front reaches a second layer 2012, a third layer 2013, anda forth layer 2014, the wave front is spread accordingly over larger andlarger spatial extents B, C, and D. As the distorting effect of thecomposite material 2005 extends over the complete wave front, the shapeof the wave front is distorted at all spatial positions within the“surface” of the wave front, which is illustrated by the largepositional fluctuation in the direction of propagation of the wave frontat the forth layer 2014.

In FIG. 20, the illustration of the deformation of the wave front is tobe understood to be explanatory with regard to an interaction of thecomposite material that can vary from layer to layer, for differenttypes and sizes of particles, etc. While FIG. 20 illustrates thedeformation based on a gradient from large to small particles, also areversed gradient can interact with an incoming wave layer by layer in asimilar manner.

At the same time, the amplitude of the compression wave is reducedduring propagation of the wave front from layer to layer indicatedthrough thinner lines for the wave fronts at subsequent layers. Thus,the form of a compression wave can be perturbed and stretched.Disruption of the wave form can further assist in diminishing thedestructive potential of a reflected wave. For example, it causesdestructive interference of a reflected and not-reflected part of thewave, thereby reducing, for example, the combined danger of bomb blastsclose to reflecting surfaces.

As explained in connection with FIGS. 7 and 8, a compression waveresulting from an explosive blast can take the form of a sharp change ingas properties on the order of a few mean free paths, for examplemicrometer scale changes in thickness at atmospheric conditions. Whilenot wishing to be bound by theory, the percentage of energy lost ordispersed as a wave travels across a composite medium based on looseparticles is not as dependent on the size and velocities of theparticles. The mechanisms can be a function of the number of particlesacross the gradient and the amount by which the particles average sizesuccessively decreases across the gradient. Thus, the normalized kineticenergy of a wave can be assumed to decay with the number of particlespresent in the composite material. Factors intrinsic to a shock wavethat can influence the propagation characteristics of a wave impacting acomposite material can include further, for example, energy flux,intensity, and pressure associated with the shock.

The reduction in energy of a shock wave can vary for any particularembodiment of a composite material. In particular, the reduction inenergy, in accordance with the various embodiments, can be a function ofone or more of the proposed contributing mechanisms. The level of energyreduction within a composite material can be analyzed by determining thecontributions from, e.g., the energy dissipated by molecular friction inview of the potential, kinetic and surface energies within the system,by rupture of the particles, and redirection of the momentum therebyreducing. While not wishing to be bound by theory, the level of energyreduction resulting from the at least partial destruction of the spatialsymmetry can be, for example, a function of the number of layers ofgraded particles, the differences in median particle sizes and masses,and other particulars of the wave form itself.

An energy balance analysis as a function of particle to particleinteraction can be calculated by determining: the geometry of eachparticle, Poisson's ratio, Young's modulus, and inter granular surfacecontact area. For two perfectly spherical particles having radii R1 andR2, and shared contact surface C12, the energy between the two spherescan be expressed as a function of contact area:

${Energy}_{c_{12}} = {\frac{8}{15}\left( {\left( \frac{1 - \sigma_{1}^{2}}{E_{1}} \right) + \left( \frac{1 - \sigma_{2}^{2}}{E_{2}} \right)} \right)^{- 1}\sqrt{\frac{R_{1}R_{2}}{R_{1} + R_{2}}}*C_{12}^{5/2}}$

wherein σ is Poisson's ratio, E is the Young's modulus, and subscripts 1and 2 refer to the individual grains. Poisson's ratio, as used herein,is defined as the ratio of the relative strain normal to the appliedload (transverse strain) divided by the relative strain in the directionof the applied load (axial strain). Young's modulus, as used herein, isdefined as a measure of the stiffness of a material, and is also knownas the modulus of elasticity, elastic modulus or tensile modulus.

Thus, a reduction in energy can be related to real time effects, suchas, for example, a reduction in shock wave amplitude, shock wave overpressure, area of fragmentation, area of blast damage, the relativedestructive power of the shock wave, and changes in the mechanicalenergy generated by the blast. In various embodiments, order ofmagnitude reductions in each component can be expected.

In other words, when subjected to the impact of a blast, the impactenergy from the blast travels across the composite material and isincreasingly deflected in different directions by the interaction withthe increasing number of contact points. This multidirectionaldeflection results in a net reduction of energy as the directionalcomponents increasingly cancel due to opposing directional components.For a gradient structure, the deflection due to a size gradient in theaverage particle sizes of a layer can also cause breakdown in thetranslational symmetry of the impact wave, further resulting in areduction of energy.

As exemplified schematically in FIG. 10, as the impact energy comes incontact with ever changing particle sizes the impact is differentiatedinto an ever changing amount of separate energies each with a distinctvector quantity, characterized by its magnitude and direction. As thedirection of the impact energy travels across the gradient it is thendeflected in different directions. The deflection results in a netreduction of energy as the directional components increasingly canceldue to opposing directional components.

Further, the impact energy could also dissipate through inter-granularfriction, re-orientation of momentum transfer and the resulting shearforces within the composite material as the shock wave traverses thecomposite material causing re-orientation of the particles.

In addition, a blast wave is also disrupted as a result of a breakdownof translational symmetry, a reduction in the blast wave energy due toincreasing attenuation, or a combination thereof.

While not wishing to be bound by theory, in one embodiment a compressionwave traveling across a composite material can be squeezed within thegradient structure due to the reduction or increase in particle sizeacross the gradient of a composite material, resulting in at least thepartial destruction of the spatial symmetry of the wave. This can alsobe expressed as a breakdown of translational symmetry, wherein asolitary wave loses its reflection symmetry and is diminished and/ordestroyed. In some embodiments, such a breakdown in translationalsymmetry can result in a significant reduction in energy.

In other embodiments, such a breakdown in translational symmetry resultsin a destruction of a wave. In other embodiments, the translationalsymmetry relates to the momentum conservation law, as described byNoether's theorem. As momentum must be conserved, the speed of thesmaller particles will increase, and thereby disrupt the wave form, andthereby reduce the increase of the destructive power of the wave, e.g.,upon reflection.

While not wishing to be bound by theory, for the gradient shown in FIG.9, the leading edge of an impact wave advances first on progressivelysmaller particles having less mass, the smaller particles can, invarious embodiments, move at a faster rate than the larger particles,resulting in a change in the propagation of the wave. Such a change canbe, for example, in the form of a non-linear increase in wavelength(stretching) of the wave, a non-linear change in the wave amplitude,and/or a change in the waveform itself. While not wishing to be bound bytheory, a similar effect on the wave form may be caused when an impactwave advances on progressively larger particles on the back side of thecomposite material 900 or within a densely packed microscale particlestructure.

As the waveform changes, the wave can, in various embodiments,experience a decrease in kinetic energy and an increase in frequency.The increase in wave form frequency, in turn increases the attenuationof the particles experiencing the waveform. The maximum attenuationachievable for a particular system can depend on, for example, the radiiand number of individual particles in the system. Thus, through theselection of materials, it can be possible to create a specific level orsystem of attenuations for a wave.

Changes, such as increases, in the attenuation of a wave can assist inthe dissipation of a wave's energy. For example, the frictionaldissipation of energy for larger, e.g., macroscale particles can be onapproximately the same scale as collision energy dissipation. Formicroscale particles (e.g., nanoscale), the frictional dissipation canbe greater than the collision energy dissipation.

In various embodiments, composite materials can provide engineeredmaterial systems, enabling the utilization of elastoplastic and finiteplastic deformation regimes, while providing control over reflection ofthe stress wave propagation to effectively dissipate shock waveprogressions.

The effect of a composite material can also be viewed based on thepropagation of the wave. Waves are transmitted through gases, plasma,and liquids as longitudinal waves, also called compression waves.Through solids, however, waves can be transmitted as both longitudinaland transverse waves. Longitudinal waves are waves of alternatingpressure deviations from the equilibrium pressure, causing local regionsof compression and rarefaction, while transverse waves in solids, arewaves of alternating shear stress. Shear stress is one way in which ourinvention reduces the energy of the wave.

Matter in the medium experiencing the wave is periodically displaced bythe compression wave. The energy carried by the wave can convert backand forth between the potential energy of the extra compression (in caseof longitudinal waves) or lateral displacement strain (in case oftransverse waves) of the matter and the kinetic energy of theoscillations of the medium.

In regards to kinetic energy, a propagating wave moves the molecules inthe medium which is carrying it, i.e. compression and rarefaction as thewave travels through the medium. In order for the compressions andrarefactions to occur, the molecules must move closer together(compression) and further apart (rarefaction). Movement impliesvelocity, so there must be a velocity component which is associated withthe displacement component of the wave. The resulting velocity is afunction of the materials (packing structure, density, stiffness, mass,inertia). Pressure is a scalar quantity and has no direction; pressurerelates to a point and not to a particular direction. Velocity on theother hand is a vector and must have direction; things move from oneposition to another. It is the velocity component which gives a wave itsdirection. The composite material changes and/or splits the velocityvector as a function of particles impinging upon one another, therebyreducing the energy in the system.

The velocity and pressure components of a wave are related to each otherin terms of the density and springiness of the medium experiencing thewave. A propagating medium which has a low density and weak spring wouldhave a higher amplitude in its velocity component for a given pressureamplitude compared with a medium which is denser and has strongersprings.

Mechanical waves originate in the forced motion of a portion of adeformable medium. Mechanical waves are characterized by the transportof energy through motions of particles about an equilibrium position. Incase of the composite material, particles of a first layer subject to anincoming compression wave are accelerated by the change in pressure andpushed in the direction of the second layer. As one layer of thecomposite material after the other is affected, the wave progressesthrough the medium. In this process the resistance offered todeformation by the consistency of the composite material, as well as theresistance to motion offered by inertia, must be overcome. As thedisturbance propagates through the composite material, it carries alongamounts of energy in the forms of kinetic and potential energies. Thetransmission of energy is affected because motion is passed on from oneparticle to the next and not by any sustained bulk motion of the entiremedium.

Deformability and inertia are essential properties of a medium for thetransmission of mechanical wave. If a medium were not deformable, anypart of the medium would immediately experience a disturbance in theform of an inertial force, or acceleration, upon application of alocalized excitation.

When, e.g., the particle diameters progressively shrink in radius bysome factor, the spatial symmetry of the solitary wave is destroyed. Theleading edge of the wave is assumed to travel progressively fasterwhereas the trailing part of the wave is assumed to travel progressivelyslower. This is due to the lighter mass of the smaller particles movingfaster than their larger neighbors. Thus, it is assumed thatprogressively less energy is carried by the leading edge.

Thus, the resulting lag and/or compression of a shock wave 20 travelingthrough a composite material can be used to muffle the shock wave 20within the composite material and, when used with, e.g., elasticmaterials, can provide a mechanical and/or electrical/magneticadvantage.

The induced change in the wave form can be utilized to provide a smartmaterial that, for example, allows utilizing a specific change in thewave form to actuate mechanical sensors or actuators incorporated intothe material or those incorporated into or on the substrate upon whichthe invention is coated. As an example, the shock wave can be used toprovide an electrical stimulus to piezoelectric materials, which in turncan actuate a variety of electrical systems.

Returning to the structural features of the composite material, itshould be appreciated that the plurality of particles can provide alevel of porosity within the composite material that depends on theparticle size. Thus, the composite material can includes voids or spaceswhere particle contact points do not exist. The porosity can be acontinuous pore microstructure within a given layer of particles or eventhroughout the entire composite material itself. Alternatively, theresulting pore microstructure can also be discontinuous with respect toa given layer of particles and even discontinuous throughout the entirematerial itself.

The level of porosity (continuous, discontinuous, or a combinationthereof) can affect material properties. When producing a compositesystem layer by layer, one can provide a layer specific porosity. Inaddition, the size of the pores differs in individual layers along theparticle size gradient. The varying densities within the compositematerial can further perturb a compression wave (amplitude, frequency,spatial form).

In some embodiments, no binding layer or intermediary material betweenthe particles is required to hold the composite material together. Insome embodiments, nanoscale and mesoscale particles but also somemacroscale particles can provide surface interaction that does notrequire a glue-like binding material and nevertheless provides theparticle sufficient mobility for momentum transfer. A similar bindingbetween a substrate and a layer contacting the substrate can be used.

For example, in some embodiments, functionalized polymer basedmicroparticles of alternating layers can provide carboxylic acid andamine groups on their surface. The coupling between the acid and basefunctionalities can be used to bind the layers. To provide, for example,a phenylsulfonic acid functionality on the surface of a substrate, polarcarbon nanoparticle (produced, for example, by Cabot Corp. with theproduct name Cabot Emperor 2000) can be incorporated in the substrate ora coating of the substrate. In particular, carbon nanoparticle basedpaint materials (e.g., jet black paint) can be used as the layer uponwhich the composite layer structure is built. For example, one wouldfirst paint a substrate with a nanoparticle paint and then apply thefirst particle layer.

As substrate materials, hydrophilic-glass or treated polycarbonate workwell. Both of these materials can be made more hydrophilic by applying alayer of poly-L-lysine or indoor Rain-X, a commercial antifoggingmaterial. An example of a binding between an 11V treated polycarbonatesubstrate and the layer contacting the substrate and between theparticles of the layers is described below in EXAMPLE 4.

In addition or alternatively, based on an adjusted pH value duringmanufacture of the composite material, one can use electrostaticinteractions to bind the layers of microparticles.

In some embodiments, some of the microparticles can carry their ownbinding coating. For example, microparticles of one of the layers, canbe functionalized with a hydrophobic coating, which is configured tohold the microparticles to a hydrophobic (polymer) surface. Thus, such abinding coating can build up an attractive force to a neighboring layerof polymeric microparticles. Thus, alternating layers within thegradient layer structure can be coated and non-coated to form thecomposite material.

In some embodiments, charged particles can be based on an ionomer(charged polymer) as a binder. If microparticles are positively chargedusing a functionalized coating, a layer of microparticles can befollowed by a layer of ionomer microparticles that binds the next layer.

The above implementations to hold particles together can be applied tothe complete composite material or only to layers of smaller (nanoscaleand/or mesoscale) particles. The implementations can be applied betweenlayers of microparticles as well as within one layer between particles.Within a composite material, the implementations can be used together iffeasible or vary within the composite material.

In some applications, one will need to complement the composite materialwith an intermediary material, which can be within the compositematerial, and/or with a binding layer (a top layer or a layer betweenlayers), such that at least some of the microparticles (e.g., the largermicroparticles of the layer structure) or all microparticles are heldtogether.

For example, a polymer filling, e.g. polymerizable monomers, a resinfilling and/or cyclodextrin filling can be used as an intermediarymaterial. The cyclodextrin can act in a similar manner as the abovediscussed ionomer. The cyclodextrin does not need to fill the poremicrostructure completely and uses electrostatics to bindmicroparticles.

In some embodiments, a resin can fill the pore microstructure and add tosome extent to or even increase the thickness of a layer. Betweenlayers, one can also add a polymer film that can be made as thin asseveral nanometers thereby adding slightly thickness to the layerstructure.

Intermediary materials can be used to fill the accessible volume. Forexample, the porosity of the composite material 900 in FIG. 9 can atleast be partially filled with an intermediary material 950. In general,the intermediary material can span a portion of at least one particlelayer, span an entire particle layer, or can even span the entirecomposite material. The intermediary material can provide some kind ofsupport for the particles without essentially affecting the mobility ofthe particles and the involved momentum transfer between particles.

The selection of an intermediary material can depend, at least in part,upon the particular desired effect and the particular end useapplication for the composite material. For example, one can introduceoil into the porosity of the composite material using capillary effect.Intermediary materials can, for example, be utilized to alter the energyabsorption characteristics of the composite material. For instance, theintermediary material can be used to augment the compression behavior ofthe material.

Alternatively, or in addition, a fire retardant can be incorporated intothe system as an intermediary material. Moreover, examples for anintermediary material can include materials that when combined viapressure and temperature, interact with the surrounding material tochange the characteristics of the resulting material to produce foam,aerogel, solgel, etc.

Furthermore, the intermediary material can change the density of a givenlayer to further disrupt the wave form of the compression wave. Theintermediary material 950 can further change the stiffness of thecomposite material 900, thereby allowing the composite material to befree standing, for example. The intermediary material can further beused to impart cosmetic or aromatic value to the composite material.

In any of the composite materials illustrated in the drawings,intermediary material can in principle be used or it can be appliedeither in whole or in part throughout the structure.

In addition to the energy absorption properties provided by the gradientlayer structure and the densely packed particle structure, the compositematerial can include core-shell particles 1100 as shown in FIG. 11. Thecore-shell particles can themselves modify the energy absorption and inaddition can provide in some embodiments a material release function tothe composite material. The core-shell particles 1100 includes acore-material 1110 (e.g., solid, liquid, gaseous, gel-type material)within a shell 1120. The core material can fill the encapsulatedmaterial completely or partly, e.g., the core is filled with differentaggregate states. Further, combinations of materials can beencapsulated. Examples for a core-shell particle 1100 include filledmicrospheres (or spheres) and other encapsulating particles thatencapsulate one or more core materials 1110. In some core-shellparticles the core can be hollow (e.g., filled with a gas).

The thickness of the shell 1120 can be, for example, between 30% and 1%of the diameter of the core-shell particle 1100. The score-shellparticle can be a microscale particle. In some embodiments using a largeamount of a specific core-material, the core-shell particles can have adiameter of several millimeters.

The shell material of the shell 1120 can be pliable such that the shell1120 can deform, e.g., upon impact of a compression wave of a bombblast. The shell material of the shell 1120 can in addition oralternatively be pliable such that the shell 1120 can deform whensubjected to, for example, over pressure. The deformation and pliabilitycan contribute to the energy absorption process.

The core-shell particles (as well as the particles in general) can bespherically or asymmetrically shaped. The shell 1120 can be a continuouswall surrounding the core or can be designed to have droplets of thecore material embedded through the microcapsule. In some embodiments,the shell can be porous.

Upon impact of a compression wave, the particle shells 1120 within animpacted layer can deform such that a portion of the energy associatedwith compression wave is therefore absorbed by the core-shell particle.As the shell 1120 deforms, it can also apply pressure to particlesadjacent to it, thus transferring a portion of the impact energy to theenergy required for subsequent deformation and angular pressure onneighboring particles.

Moreover, to provide specific features in a, pre-blast environment, forexample, the core material can be configured to have various features.For example, it may operate as RF shielding to impede remote detonationof bombs.

Additionally, or alternatively, the core material 1110 can, for example,include an agent material (e.g., a secondary blast agent), the presenceof which can be utilized to interact with secondary blast effects in apost blast environment in a predetermined manner. For example, in oneembodiment, the core-shell particles 1100 can encapsulate one or moreagent materials capable of mitigating and/or remediating secondary blasteffects, such as flash, fire, chemical agent release, biological agentrelease, radiation release, and shock wave caused damages. To that end,agent materials can include without limitation, fire retardants, flashsuppressants, medicinal treatments, and the like.

The core-shell particle 1100 can also encapsulate one or more agentmaterials that when combined through actuation or actuation and rupture,can interact with each other or with the blast environment to produce adesired effect. For example, in one embodiment it is contemplated thatseparate agent materials can be encapsulated such that when combinedthrough rupture of several core-shell particles 1100 the materials reactto generate fast setting structural foam. Such foam can, for example,assist in mitigating and/or remediating oil loss from ruptured pipelinesas explained in connection with FIG. 18 below.

In use, the shell 1120 of the core-shell particle 1100 can deform underthe impact pressure from a shock wave to a deformation where shellrupture occurs, thus releasing the core material 1110 as an agentmaterial, e.g., a secondary blast agent, which is thereby directlyreleased into the blast zone. The released agent materials can thendirectly interact with the environment to mitigate and/or remediate,e.g., one or more secondary blast effects.

Moreover, it is contemplated that by exposing an agent material to acombination of relatively large pressure and heat changes, the releasedagent material can, for example, be consumed in or can otherwiseparticipate in a reaction that produces further reaction products thatcan also be beneficial to remediation and/or mitigation of blasteffects.

As shown in FIG. 12, core-shell particles can form a composite material1200 that can be applied as a coating or as a film to a substrate 1210,for example, before or after applying a gradient layer structure. Thecomposite material 1200 includes three mono-dispersed layers ofcore-shell particles 1220, 1230, and 1240. The core material of thelayers 1220 and 1240 is indicated to be the same (vertical hatching) andto be different from the center layer 1230 (diagonal hatching). Undercertain conditions, e.g., under high pressure caused by an explosion,the shells of the core-shell particles rupture and release the corematerial. The core material can provide mitigation for itself and/or incombination and/or after reaction with each other. The functionality ofthe composite material 1200 can thereby be adapted to the specificapplication.

Thus, as shells rupture in successive layers, agent materials containedin different core-shell particles can be sequentially introduced intothe blast zone allowing more complex systems to be introduced andallowing sequential reactions to occur in a predefined manner. Thisstaggering of additional agent materials (secondary agent materials,tertiary agent materials, quaternary agent materials, etc.) in apre-designed manner can further allow sequential reactions whose sumreaction is greater than their individual contributions.

The composite material 1300 of FIG. 13 includes a single mono-dispersedcore-shell particle layer 1310, a gradient layer structure 1320, adensely packed particle structure 1325, and a substrate 1330.

Mono-dispersed layer 1310 made of core-shell particles is provided infront of gradient layer structure 1320. Moreover, layer 1335 of thegradient layer structure 1320 includes core-shell particles and layer1345 of the densely packed particle structure 1325 includes alsocore-shell particles. Thus, the advantages of the composite material canbe combined with the advantages of the core-shell particles. This allowsfurther adapting threshold conditions within the gradient layerstructure for the release of the core-material.

Similarly, core-shell particles can be included in concentric gradientlayer structures. In FIG. 14, a composite material 1400 includes as acenter particle a core-shell particle 1410. A layer 1420 having athickness of multiple particle diameters is formed around the core-shellparticle 1410 as a densely packed particle structure. Then, threeconcentric layers 1430, 1440, 1450 consisting of mono-dispersedparticles of increasing size are applied. An intermediary material 1460provides structural cohesion of the particles.

FIG. 55 shows a cross-section of a densely packed particle structurethat includes (from left to right) a core-shell particle size small, asolid particle size small, a core-shell particle size large, a solidparticle size small, a solid particle size large. Due to the differencein size, the small particles can fill spaces between the large particlesthereby interlocking the different particle layers.

Plotting the size of the particles over the layers provides access tothe type of structures included in a composite material. For some of thepresented examples, the particle size dependence was illustrated inFIGS. 43 to 45. However, the composite material is not restricted to twoor three structural units, where a structural unit is a gradientstructure or a densely packed structure. (It is noted that also agradient structure includes densely packed particles but with theadditional requirement of a particle size gradient). One can repeatstructural units, alternate structural units, repeat combination ofstructural units, or combine different combinations of structural units.

Additional examples of combinations of structural units are shown inFIGS. 46-48. In the configuration shown in FIG. 46, a gradient structureis provided on each side of a densely packed particle structure, suchthat on both sides small particles form the outer surface, i.e., thegradients have opposite direction.

In the configuration shown in FIG. 47, two outer gradient structuresform gradients in different ranges of particle sizes with largeparticles form the outer surfaces. An inner densely packed particlestructure includes also larger particles.

In the configuration shown in FIG. 48, densely packed particlestructures of different particle sizes and thicknesses form a sandwichstructure with an inner one-directional gradient structure.

As discussed herein, the particles of the gradient structures anddensely packed particle structures can be solid particles or core-shellparticles. FIGS. 49-54 illustrate various examples of distributing andmixing these particles with in a composite material. A similar freedomexists for different types of particles, such as shapes, materials etc.

In FIG. 49, two densely packed particle structures of different size arein contact with each other, one having exclusively solid particles andthe other exclusively core-shell particles. Even though three particlesare indicated, each densely packed particle structure may have 10, 20,30, . . . 50, 60, . . . 100 layers or a thickness of 10, 20, 30, . . .50, 60, . . . 100 (non-layered particles). In addition, the layers maybe looser so that there is some overlap between neighboring layers asdescribed above. For small numbers of particles for each size, one mayrepeat the sequence of the two sizes to form a densely packed particlestructure.

While in FIG. 49 the particles of each type were essentially of the samesize, FIG. 50 shows an embodiment in which each type of particle coversa range of sizes that are randomly arranged within each densely packedparticle structure. Even though the first and the last particle ofdensely packed particle structure may not have the same size, thisdifference is not considered to be a gradient in view of the fluctuationof the particle size. While the solid particles of the densely packedparticle structure having a smaller size has the same size in the firstand fifth layer, the core-shell particles of the first and fifth layerdecrease slightly in size. Due to the fluctuation in particle size ofthe core-shell particles, the second layer from the right has even asmaller size than the fifth layer.

FIG. 51 illustrates that particles within a densely packed particlestructure can include solid and core-shell particles either within arange of particle sizes (left side) or with the same size (right side).

While FIGS. 49 to 51 referred to two densely packed particle structuresonly, FIGS. 52-54 illustrate similar particle size distributions forgradient structures and densely packed particle structure (FIG. 52),densely packed particle structure and gradient structures (FIG. 53), andfor two gradient structures (FIG. 54).

Based on the above described composite materials, exemplary applicationsare described in connection with FIGS. 15-19, 21-24, and 42.

FIGS. 15 and 24 illustrate the application of the composite material inthe context of waste receptacles. In FIG. 15, the composite material isattached to a support structure of a container 1500, forming forexample, the structural basis for a waste receptacle. The inner surfaceof the container 1500 is coated with a composite material 1510 includinga gradient layer structure and a densely packed particle structure thatforms the inner surface of the container 1500. The composite material isrepresentative for various configurations of the composite material, andthe combinations of gradient layer structures, densely packed particlestructure, and core-shell particle layers as discussed within thisapplication, for example, in connection with FIGS. 3-6, 9, 11-14, 22,and 24, whereby the directions of the gradients illustrated in thosefigures is only exemplary and can be for example, reversed or vary indirection and strength.

Thus, any explosion initiated within the container 1500 and generating ashock wave is reduced in its destructive power because the shock waveloses intensity when traveling through the gradient layer structure andwhen reflecting from the coated walls of the container 1500.Additionally or alternatively, the outer surface of the container can becoated with a gradient layer structure.

Moreover, instead of being applied as a coating, the composite material1510 can be attached as a film or panel. In some configurations, thesupport structure can be only a frame and the composite material forms,for example, transparent walls to that frame.

Alternatively, or in addition, the waste receptacle itself may consistentirely of the gradient layer structure as will be discussed below inconnection with FIG. 24.

Moreover, the composite material can be transparent, opaque, ornon-transparent and it can be manufactured, for example, as a film or asa bag, e.g., a waste receptacle liner. Moreover, it can be made asindividual bags or in rolls, which separate at serrations. The film canbe applied onto a substrate of any shape. The composite material canmitigate and/or remediate by absorption and dissipation in apredetermined manner, for example, effects of a bomb blast, whichoriginates on either side of the composite material. In addition, thecomposite material can use the shock wave to mitigate and/or remediatethe bomb blast by rupturing and/or vaporizing core-shell materials, suchas microcapsules, which populate the gradient layers as one of thegradient layers or as a layer attached to the gradient layer structure.The core-shell material can be hollow or filled with material(core-material), concentric and/or non-concentric as discussed withinthis application.

Materials suitable as core material for core-shell particles of acore-shell particle layer, e.g., next to a gradient layer structure 1510or forming a layer within the gradient layer structure 1510 or thedensely packed particle structure, include flame retardants andsuppressants, foam-generating materials and dispersants, materials whichsuppress and/or deform acoustic waves, materials which suppress smokeand dust, for example. The core material can further contain materialsassociated with medical treatment, for, for example, burns, infection,inflammation, pain, antibiotics, and materials used for triage medicaltreatment, materials which impede RF transmission, and/or electricalimpulses, in order to reduce the risk to first responders from secondarydevices placed and planned to be activated by remote signal, andmaterial which impede the dispersal of biological and radioactiveagents.

The composite material can further contain a sensor material thatchanges color when activated by a specific chemical signature of matterin its environment, e.g., carried by solid particles, gases, and/orliquids. The sensor material can be contained in the particles of thecomposite material, e.g., in filled or hollow microspheres and/orcore-shell particles of the gradient layer structure 1510 and/or acore-shell particle layer (e.g., core-shell particle layer 2220 in FIG.22). The sensor material can additionally, or alternatively be containedin a film or coating material, e.g., forming an outside surface of thecomposite material. Moreover, in addition, or alternatively, the sensormaterial can be contained in a binding layer (e.g., binding layer 2440in FIG. 24) and/or in an intermediary material of the composite material(e.g., intermediary material 950 of in FIG. 9).

For example, explosives that release a (gaseous) material with aspecific chemical signature can yield a concentration above apredetermined concentration in, e.g., a closed or partly closed wastereceptacle. Then, the sensor material acts as a (chemically triggered)sensor and identifies the presence of the explosive in the wastereceptacle by changing its color. The composite material with the sensormaterial can be part of a waste receptacle or of a waste receptacleliner or any structure subject to be used for hiding an explosive.

Example sensor materials for detecting explosives such as C-3, SemtexH,and TNT include a mixture comprised of zinc, glacial acetic acid and theNitriVer 3 Reagent supplied, e.g., by the Hach Co. (Cat #1407899). Thesematerials can be combined in solution with water and can then be appliedas a sensing film that is dried onto the gradient layer structure, ontothe core-shell particle layer, and/or in between particle layers. Inaddition, or alternatively, these materials can be presented separatelyas, e.g., microscale particles (such as nanoscale particles) or coatingson microscale particles (such as nanoscale particles) in the gradientlayers. Example particles that can be coated include, for example, zincparticles and polymer particles with acid groups. Moreover, thematerials can be provided as a shell material of a core-shell particle.The reaction and detecting of, for example, TNT or RDX as describedabove can be adapted from the method as described in EPA METHOD 8510“COLORIMETRIC SCREENING PROCEDURE FOR RDX AND HMX IN SOIL” Revision 0,U.S. Environmental Protection Agency, February 2007(http://www.epa.gov/SW-846/pdfs/8510.pdf), the contents of which arehereby incorporated by reference in their entirety.

The inner layers of the composite material 1510 can provide gradientlayer structures and densely packed particle structure with particles insize and sequence such that a distortion of the compression wave isachieved. Moreover, the reflected wave can be distorted and/ordiminished such that, for example, the primary and secondary effects ofthe combined compression wave (based on the reflected wave and theinitial compression wave of the bomb blast) are at least to some degreemitigated and/or remediated.

An inner layer of the composite material, with which a person usuallycannot get in contact, can also include particles (microparticles,core-shell particles etc.) that contain a rodenticide for, e.g., ratcontrol. In case of a bomb blast, the rodenticide vaporizes and/orincinerates and would not harm the environment. The layers, whichcontain the rodenticide, can be changed by generation of manufacture toaccount for the evolution of immunities in the area's rodent population.

As noted above, the composite material 1500 and the composite material2400 can alternatively, or in combination, also be implemented in aliner that is used with a waste receptacle or used as a separate bag forwaste material. In some embodiments that apply the composite structureto waste receptacles, the composite material as part of the liner or thereceptacle is transparent.

When, for example, a bomb detonates within the container (wastereceptacle), by the use of a timing device, (because RF shielding makesdetonation by a radio signal sent to a cell phone or other radioreceiver at the bomb ineffective), layers of the composite materialclosest to the detonation absorb the blast energy and cause rupture ofthe core shell particles within the composite material, which releasetheir contents. As the shock wave moves through the composite materialto the inner layer particles, deformation of the shock wave increases.

Further, as the shock wave propagates, the core-shell particles rupturein a predetermined sequence and can introduce materials into the blastenvironment that act, for example, as a flame retardant and dispersantand suppressant, sound suppressant, smoke and dust suppressant. Thecore-shell particles can further introduce into the environmentmaterials that are used to treat burns and other wounds, impede thedispersal of biological and radioactive agents, as well as RF shieldingmaterials and materials which impede electrical impulse, designed toreduce the risk to first responders from a second detonation caused byother devices placed and planned to be triggered by a remote signalafter their arrival to aid blast victims.

In other embodiments, fibers and textiles, in general, sports equipment,helmets, helmet liners or helmet liner pads, and any existing structureor item can be coated or provided with a film as illustrated, forexample, in FIGS. 16, 17 and 22. Fibers can be woven into cloth andthereby shield the wearer at least partly from an impacting compressionwave. The coated fiber 1600 of FIG. 16 includes a core fiber 1610 thathas been coated with a sequence of mono-dispersed layers 1620 ofparticles with increasing size. The particles are confined through anintermediary material 1630. Alternatively, one could form a similarstructure without the core fiber 1610 or remove the core fiber 1610after the gradient layer structure has been formed. As indicated above,densely packed particle structures can be formed by one or more of thegradient layers or by applying densely packed particle structures nextto the gradient structure.

In FIG. 17, an alternative coated fiber 1700 includes a core fiber 1710that has been coated with the concentric composite material 1400 of FIG.14. Different core-materials 1720 and 1730 for the composite material1400 are indicated. A cloth including the coated fiber 1700 providesmitigation and/or remediation of an incident compression wave andadditionally can provide agent materials, such as medicine or flamesuppressants and retardants. Thus, agent materials can be introducedwhere they are needed the most upon impact of a bomb blast. Similarly,sports equipment, a helmet, helmet liner or helmet liner pads can becoated with composite materials of that kind as discussed in connectionwith FIG. 21. Alternatively, the helmet, helmet liner and helmet linerpads can be made with composite materials of the kind discussed inconnection with FIG. 21. As indicated above, densely packed particlestructures can be formed by one or more of the gradient layers or byapplying densely packed particle structures next to the gradientstructure.

Destructive compression waves can also be generated under differentconditions. For example, the opening and closing of valves in pipelinesystems can generate compression waves, even shock waves that propagatealong the pipes and can cause damage, including the rupture of the wallsof the pipes. FIG. 18 shows schematically a pipe 1800 with a valve 1830.To reduce the risk of compression wave induced damage, the inside of thepipe 1800 can be coated with a composite material 1810 including agradient layer structure, a densely packed particle structure, and anintermediary material 1815. The gradient can be formed perpendicularand/or parallel to the walls of the pipe 1800. A compression wave 1820generated when operating the valve 1830 will then decrease in amplitudewhen impacting onto or traveling along the walls of the pipe 1800.Additionally, or alternatively core-shell particles can be included inthe composite material 1810, thereby providing a core material for,e.g., mitigating the damage of leaking oil or sealing hair fractures ofthe pipe 1800. In addition, or alternatively, the outside can be coatedsimilarly.

Thus, applications of the composite material can include the mitigationand/or remediation of a compression wave, caused by, e.g., a bomb blastor the opening or closing of values, traveling along pipelines and otherconduits used for transport of liquids and gases, to include fossilfuels, flammable liquids, and waste materials and to mitigate and/orremediate fire, leakage, release of gases and/or other effects. Thecomposite material can be manufactured into a casing, outer and/or innercoating, cladding, film or liner. The composite material can further bedesigned to alleviate stress and fatigue caused by experiencing extremechanges in temperature.

In the following, the case of fossil fuel pipelines is discussed as aspecific example in greater detail. Especially in areas with risk ofasymmetrical warfare, pipelines can be provided with layers of thecomposite material on the inside and/or on the outside. Then, thecomposite material can mitigate and/or remediate the effects of a bombblast by absorption and dissipation in a predetermined manner, which canoriginate on either side of the material. In addition, one can use thewave to mitigate and/or remediate effects of the bomb blast and theleaking, eventually burning oil, by rupturing and/or vaporizing, e.g.,core-shell particles, which populate specific layers within or next tothe gradient layer structure of the composite material. Particles of theoutside gradient layers, for example, can contain flame retardants andflame suppressants, foams and dispersants, smoke suppressants. Somecore-shell particles can further include materials associated with thetreatment of burns, infection, inflammation, pain, antibiotics, andmaterials used for triage medical treatment. Other core-shell particlescan contain a material that blocks RF transmission, and impedes thedispersal of biological and/or radioactive agents.

The interior layers of the composite material are configured in agradient layer structure to cause maximum disruption of shock wave anddiminishing of the reflected wave. Some particles within or bordering tothe gradient layer structure can be core-shell particles containingsurfactants, which can break down and aid in the dispersal of fossilfuels in order to mitigate and/or remediate its effect on theenvironment. Inside and/or outside layers can contain core-shellparticles with a core material that alleviates stress and fatigue causedby experiencing extreme changes in temperature.

When, for example, a bomb detonates next to the pipeline, the outerlayers of the composite material closest to the detonation absorb theblast energy and cause thereby the rupture of the hollow particles andcore-shell particles, which release their contents. As the shock wavemoves through the composite material, deformation of the blast waveincreases. Further, as the wave reaches those core-shell particle layersone after the other, the rupture of core-shell particles can occur in apredetermined sequence to provide a flame retardant and suppressant,generate non-flammable foam, and/or other coagulants designed to containthe flow of materials thereby preparing the area for decontamination andcollection of the material released by the effect of the blast into theenvironment. Contemporaneously, the composite material can introduceinto the blast's target environment the materials that treat burns andother wounds or impede the dispersal of biological and radioactiveagents. It can further introduce into that environment RF shieldingmaterials.

In FIG. 19, a hand held device 1900 is coated with a composite material1910 to increase the resistance against impacts by affecting thepropagation of a shock wave caused by, e.g., falling onto the ground.Alternative examples, for devices that can profit from shock absorptionas explained, for example, in connection with FIG. 20 include laptops,cell phones, audio devices, and e-books.

FIG. 21 illustrates the application of the composite material in thecontext of a shielding device, specifically, a helmet 2100. The helmetincludes a helmet structure 2110 to which helmet liner pads 2120 areattached. It is common to wear a helmet just with those helmet linerpads in certain environments. In addition, one can wear the helmet 2100with a helmet liner 2130 that can give additional shelter for a specificenvironment (temperature, sun light, wind, sand, etc.). In someconfigurations, one uses the helmet liner 2130, for example, a coldweather helmet liner, with the helmet liner pads 2120. A compressionwave caused by a sports impact, detonating bomb or hitting a hardsurface, e.g. pavement, can be mitigated and/or remediated based on thecomposite material including a gradient layer structure, a denselypacked particle structure, and/or a core-shell material, which mitigateand/or remediate by absorption, dissipation, and providing corematerials in a predetermined manner the effects of the compression wavestriking the helmet 2100. The composite material can be incorporatedinto the helmet liner pads 2120 and/or the helmet liner 2130 and/or thehelmet structure 2110.

The composite material, in addition to mitigating the effects of thecompression wave, can signal concussive injury with or withoutpenetration of the helmet 2100. It can provide immediate treatment ofwounds with antibiotics, anti-inflammatories, pain medicine and bloodcoagulants, for example, for helmet penetrating and non-penetratingevents before triage medical treatment. The composite material cantherefore maximize the comfort of the helmet wearer while providingvarious safety features.

The composite material can be either applied directly onto the helmet asan inside and/or outside coating 2140. The composite material canfurther be incorporated in the helmet liner pads 2120 and/or the helmetliner 2130. Different composite material can also be provided in aseries of pad elements 2121, 2122, 2123 thereby providing specificfeatures at different locations. In some applications, the exteriorlayers of the pads closest to the wearer are designed to wick awaymoisture.

The material of the composite material can be self-extinguishing whenexposed to combustion. The material can be a material that vaporizesand/or otherwise become a material, which will not drip, therebyprotecting the scalp and skin of the wearer of the helmet 2100 fromburns and aggravation of head and/or neck injury.

An exemplary structure for the series of pad elements 2121, 2122, 2123is shown in FIG. 22. The microcapsules in the composite material rupturewhen impacted at different levels of force. The composite material thatis closest to the scalp and skin and closest to the helmet structure isbased on a gradient layer structure 2210, 2230. In FIG. 22, only onegradient layer structure and one densely packed particle structures nextto the gradient structure is shown within the pad elements 2210 and 2230but many more gradient layer structures with gradients of variousdirections and amplitudes and densely packed particle structures can beused. In general, the gradient layer structures 2210, 2230 each can besequenced to increase the absorption of the compression wave.

The gradient layer structures of the pad elements 2210 and 2230 closestto the scalp and skin can further include core-shell particles 2240,2250 with core materials such as flame retardants and suppressants,materials that wick away moisture, antibiotics, anti-inflammatories,pain medicine and blood coagulants.

The composite material of an intermediary pad element 2220 can include adensely packed particle structure of core-shell particles that provideafter rupture an inelastic non-toxic inflammable foam. The foam canexpand into a space 2150 between the head and the helmet structure 2110thereby stabilizing the helmet head system and any head injuries. Inaddition, or alternatively, the foam can be contained within the helmetliner pad or pads and/or the helmet liner thereby increasing their sizeand tightening the helmet to the head. Thus, the inelastic foammitigates and/or remediates by absorption and by keeping the helmetproperly seated to protect the skull from further impacts and exposureto, e.g., the heat from combustion.

The helmet liner and/or the helmet liner pads can be made completely ofpure composite material pad elements as shown in FIG. 22. Alternatively,a pad can include a cushioning material around which (or in betweenlayers of the cushioning material) the composite material is wrapped ina textile like structure. For example, the intermediary pad element 2220can be replaced with a cushioning material.

In some embodiments of the pads or the helmet liner, the compositematerial can include core-shell materials that contain a non-toxic, andwashable, dye. Assuming that there is no penetration of the helmet 2100,when impacted by a compression wave, the gradient layer structuresclosest to the helmet mitigate and/or remediate the force of thecompression wave. However, if the force of the impact is within aspecified range, the composite material acts as a (physically triggered)sensor when the color filled core-shell particles rupture and mark theareas of impact or the occurrence of a compression wave.

When the helmet is removed, it is possible to determine that the wearerhas sustained a possible concussive injury even though there is nopenetration of the helmet. If the dye is triggered, after the helmet isexamined and/or the wearer, this may indicate a possible concussiveinjury. In some applications, the dye can then be removed when washed.

The gradient layer structures continue to interact with followingcompression waves.

The layers closest to the skull, in addition to absorbing the impact,can also direct the force away from most sensitive areas of the skullthereby using the compression wave against itself to maximize thedistortion of the compression wave.

Even in the case of a penetration of the helmet 2100, the core-shellparticles closest to the skull, which can contain antibiotics and bloodcoagulants will rupture within the region of penetration, and therebydelivering their content into any wounds created and mitigating and/orremediating by triage treatment designed to stabilize medicalconditions, prevent infection and to aid in cauterizing the wound.

The above discussed features can similarly be implemented in, e.g.,different layers of a “cold weather” liner. Thus, the helmet liner 2130itself can contain a composite material with core-shell particlesproviding various materials, when ruptured. In addition to absorb theblast wave, the generated foam can also protect against and treat neckwounds and provide acoustic protection as the foam can cover the neckand the ears of the wearer.

Due to the modular concept, the helmet liner pads 2120 and/or the helmetliner 2130 can be replaced after the mitigation and remediation of animpact or if some core-shell particles have ruptured or exchange isappropriate.

The above discussed features can similarly be implemented within theinside and/or outside coating 2140, which can be reapplied if necessary.

Example helmets include combat helmets and sport helmets, such asfootball helmets, hockey helmets, baseball helmets, bike helmets, ridinghelmets, and motor cycle helmets.

The composite material can further be applied in form of a panel, e.g.,a piece of molded composite material which you can attach to either aspecific part, the door of a vehicle, for example, or which you canattach to a plate, like those suspended from the side of assaultvehicles. The panel can further be easily transported and mounted tobuilding or any object (large or small) that can benefit from shieldingagainst compression waves.

In the following, the composite material is discussed in the context ofshielding a transportation device, for military and/or civilian use.FIG. 23 shows schematically a transportation device 2300 such asvehicles, ships, boats, and aircraft, (airplanes, helicopters, spaceships, etc.) or a part thereof. The transportation device can be mannedor unmanned. It can transport people, surveillance devices, measurementdevices, ordinance, or goods. Specific examples include tanks andHumvees (e.g., exterior shielding), airplanes, and helicopters (e.g.,body, cockpit glass, engine, ordinance, and rotor blade shielding),unmanned drones used for surveillance and/or as a weapons platform(e.g., body, engine, optics, exterior and ordinance shielding), shipsand submarines (e.g., hull and wall shielding).

The composite material can be applied to a surface of the transportationdevice 2300 as a coating 2310. Alternatively or additionally, thecomposite material can be attached to the surface as a removable unit2320, e.g., as a film or panel that fits to and is shaped according tothe shielded surface. Alternatively the composite material can be usedas filling material for cavities of outer wall structures of thetransportation device 2300, e.g., to fill the outer walls of ships orthe doors of cars with, e.g., granular composite material based onconcentric gradient layer structures.

The composite material mitigates and/or remediates the effects of ablast and/or impact through its structure and by using that force as anactivator to rupture and/or vaporize core-shell materials containingcore materials, which are, e.g., flame retardants and suppressants, foamgenerators and dispersants, smoke suppressants, materials which canimpede RF transmission and electrical impulses, materials associatedwith the treatment of burns, and other wounds, infection, inflammation,pain, antibiotics, and materials used for triage medical treatment, andmaterials which act as a shield against biological and radioactiveagents. The composite material can be transparent when applied, e.g., toglass, polycarbonate resin, or other materials used for viewing withoutessentially distorting visibility and degrading over period of use andexposure to extreme changes in temperature.

For example, for a vehicle, the composite material can be applied as afilm attached to the surface of the vehicle, or can form completelymolded panels attached to the sides, bottom and top. The compositematerial can be re-applied in field conditions after the compositematerial is triggered by a bomb blast. When used as a panel, as acoating, or as a film, the composite material can be light in weight.The outer layer of such a panel and/or film closest to the vehicle cancontain a resin to bind it to the vehicle.

When, for example, a bomb detonates in the vicinity of the vehicle(representative for any transportation device), the outer layers of thecomposite material closest to the blast absorbs the blast energy causingthe rupture of core-shell particles, the latter releasing the flameretardants, dispersants and suppressants, the smoke suppressants, aswell as injecting into the targeted environment materials used to treatburns, and other wounds, infection, inflammation, pain, antibiotics, andmaterials used for triage medical treatment. Additionally, the compositematerial can introduce into that environment RF shielding materials orother materials to impede the transmission of electric impulses andthereby to reduce the risk to personnel already on site and to firstresponders from another bomb triggered by a remote signal following theinitial blast. Materials to impede biological agents and radioactivitycan also be introduced into the target area.

As the shock wave moves from the outer layer through the compositematerial, to the inner layer particles, deformation of the blast waveincreases. Contemporaneously, the shock wave activates core-shellmaterials within the composite material, while at the same time theinner layers direct the shock wave in a predetermined manner.

In FIG. 24, a waste receptacle 2400 consists entirely of a compositematerial that includes gradient layer structures 2410 and 2415 andcore-shell particles 2420 and 2430. The core-shell particles can be partof the gradient layer structure as illustrated for the core-shellparticles 2420 in the gradient layer structure 2415. The core-shellparticles can further form a layer themselves as illustrated for thecore-shell particles 2430. The outer particles of the composite materialcan be confined by a binding layer 2440. The binding layer can include,for example, a sensor material that changes color in response to achemical signature in its environment. The binding layer 2440 canalternatively or additionally be provided between layers of thecomposite material, e.g., between the core-shell particle layer 2430 andthe gradient layer structure 2420. As discussed above one or more layersof the gradient layer structure can include multi-particle layers andthereby form densely packed particle structures. Additionally oralternatively, one or more densely packed particle structures can beincluded next to the gradient structure 2420.

Materials suitable as core material of the core-shell particles 2420,2430, include flame retardants and suppressants, foam-generatingmaterials and dispersants, materials which suppress and/or deformacoustic sound waves, materials which suppress smoke and dust, forexample. The core material can further contain materials associated withthe treatment of burns, and other wounds, infection, inflammation, pain,antibiotics, and materials used for triage medical treatment. Moreover,materials can include RF transmission blocking materials that impedeelectrical impulses, and/or materials, which impede the dispersal ofbiological and radioactive agents in order to reduce the risk to firstresponders from secondary devices placed and planned to be activated byremote signal. The core material can fill the shell completely orpartly, and can be provided itself as core-shell particle(s), such asmicrocapsules.

One can manufacture the complex structure of the composite material forthe waste receptacle layer by layer or attach pre-manufactured, e.g.,layer sequences. The composite material can moreover be used in the formof a clear or opaque material.

As a shell material and/or a core material of the core-shall particlelayers 2420 and 2430, the composite material can include a material thatchanges color (for example, in response to gaseous chemical signaturesof explosives as discussed above in connection with FIG. 15), firesuppressant, and/or a rodenticide. For example, those materials can bepresent in the surface layer, or any inner layer of the compositematerial.

Additional applications can involve the suppression of compression wavesto make wall structures or windows safer. As shown in FIG. 42, a safetyglass 4200 includes two side windows 4210. A composite material 4220 ispositioned between the two side windows 4210. To be transparent, theparticles of the composite material can be made of, for example, silicaor glass. Also small size polymer nanoparticles of the order of 100 nm(e.g., polystyrene particles) can also be essentially transparent. Sidewindows 4210 are at least partly transparent and can be made, forexample, of polymers (e.g., polycarbonate). Composite material 4220 canbe attached to at least one of the side windows 4210. In safetyapplications, the composite material can be applied, for example, as acoating or film.

Alternatively, composite material 4220 can be, for example, positionedas a self-supporting foil between the two wide windows 4210. Alsocomposite material 4220 is at least partly transparent.

The structure as described in FIG. 24 can similarly also be the basisfor a waste receptacle liner or any of the herein described embodiments.In general, any structure and use of material in any of theconfiguration described herein with reference to a specific applicationof the composite material can be applied in a similar way to anotherapplication or configuration of the composite material. Forsimplification, the various configurations and applications of thecomposite material were discussed based on drawings showing primarilylayers that consist of essentially a single particle in direction of thethickness of the layer. However, each of the illustrated layers can inprincipal be a mono-dispersed layer or multi-particle layer and therebybe representative for a densely packed particle structure. In thefollowing FIGS. 25 to 27, composite materials with multi-particle layers(two layers again being representative for two and more layers) arediscussed in more detail. These or similar composite materials can beused in embodiments as described for example, in connection with FIGS. 1to 6, 9, 13 to 24.

For example, while FIGS. 1 and 2 show generic embodiments of compositematerials 100 and 200, respectively, FIG. 25 shows an embodiment of acomposite material 2500 with a particle size gradient formed bymono-dispersed and multi-particle layers. Specifically beginning at thesmall-particle side, two mono-dispersed layers 2510 and 2520 are denselypacked. A first multi-particle layer 2530 comprises two densely packedsub-layers 2530A, 2530B and a loosely packed sub-layer 2530C. Sub-layer2530C interleaves with loosely packed mono-dispersed layer 2540 that onthe other side interleaves with a first of three loosely packedsub-layers 2550A to 2550C of multi-particle layer 2550. The largestparticles form a multi-particle layer 2560 of two densely packedsub-layers 2560A and 2560B, being a two layer densely packed particlestructure.

In densely packed mono-dispersed layers and densely packedmono-dispersed sub-layers (e.g., mono-dispersed layer 2510 and sub-layer2560B), particles are in contact with the neighboring particles withinthe layer and sub-layer, respectively. In contrast, particles of looselypacked mono-dispersed layers or sub-layers are mostly not in contactwith the neighboring particles within the layer and sub-layer but are incontact with particles of neighboring layers/sub-layers. In general,regions with loosely and densely packed particles can both be presentwithin a mono-dispersed layer or sub-layer.

FIG. 26 shows an example of a composite material 2600 that provides agradient that changes direction similar to FIG. 9. Specifically,composite material 2600 includes two symmetric layer sequences 2600A and2600B as shown in FIG. 25 for composite material 2500 that are attachedto each other at the small-particle side, thereby forming amulti-particle layer 2610 comprising two mono-dispersed sub-layers 2610Aand 2610B (being a two layer densely packed particle structure) in themiddle of composite material 2600.

Similarly for concentric configurations as shown generally in FIG. 6, aspecific embodiment of a concentric composite material (a concentricallylayered particle structure 2700) is shown in FIG. 27 that includes amono-dispersed layer and a multi-particle layer, which are orientedconcentrically around a central particle 2710. Central particle 2710 issurrounded by a multi-particle layer of a densely packed sub-layer ofparticles 2720A and a loosely packed sub-layer of particles 2720B. As asurface layer, a mono-dispersed layer includes loosely packed pluralityof particles 2730 that partially fill the space between loosely packedparticles 2720B. Thus, the mono-dispersed layer overlaps partly with theloosely packed sub-layer. Central particle 2710, sub-layers 2720A,2720B, and mono-dispersed layer 2730 form a gradient layer structurewith decreasing particle size with increasing radial distance from thecenter of central particle 2710. In some configurations, sub-layers2720A, 2720B are representative for a two layer densely packed particlestructures and mono-dispersed layer 2730 does not need to berepresentative for mono-dispersed layers of a gradient. In someconfigurations, sub-layers 2720A, 2720B are not representative for adensely packed particle structure but mono-dispersed layer 2730 isrepresentative for densely packed particle structures.

In contrast, a concentrically layered particle structure 2800 is shownin FIG. 28 that is configured to form a gradient layer structure havingincreasing particle size with increasing radial distance from the centerof central particle 2810 with the exception of that central particle2810 being the largest particle. Concentrically layered particlestructure 2800 includes further a layer with the two densely packedmono-dispersed sub-layers 2820A, 2820B and a densely packedmono-dispersed layer 2830 is shown as a surface layer. Similarconsideration with respect to the interpretation of the structure can bedone as above for FIG. 27.

While FIGS. 27 and 28 specifically describe multi-particle layers forconcentric layer structures, FIGS. 29 to 32 describe multi-particlelayers for planar layer structures.

In particular, FIG. 29 shows a composite material 2900 of 6multi-particle layers applied to a glass or polycarbonate substrate2970. The mean particle size multi-particle layers decreases withincreasing distance to substrate 2970. Specifically, composite material2900 includes multi-particle layer 2910 comprising 3 sub-layers of 320nm polystyrene particles, multi-particle layer 2920 comprising 4sub-layers of 260 nm polystyrene particles, and multi-particle layer2930 comprising 5 sub-layers of 220 nm polystyrene particles.Multi-particle layers 2910 to 2930 are hexagonal close packed (hcp)layers. Gradient layer structure 2900 includes further multi-particlelayer 2940 comprising 6 sub-layers of 160 nm polystyrene particles,multi-particle layer 2950 comprising 4 sub-layers of 130 nm polystyreneparticles, and multi-particle layer 2960 comprising 2-4 sub-layers of110 nm PMMA particles. Multi-particle layers 2940 to 2960 are cubicclose packed (ccp) layers. While, for example, layers 2910 to 2920 mayact as densely packed particle structures, layers 2930 to 2960 may actmore like a gradient structure or visa-versa depending on the physicalproperties of the particles. However, this structure is only exemplaryto illustrate the various aspects of densely packed particle structuresand gradient structures. In principal, densely packed particlestructures may include large numbers of layers comparable to the numberof gradient layers.

Composite material 2900 is held together without a binding material. Itis assumed that the binding is caused by hydrogen bonding of acidicfunctions of the material.

Composite material 2900 can be produced by spin coating using particleconcentrations of about 2.5% for layers comprising 3-4 sub-layers. Ithas been found that lower concentrations of about 1% for largerparticles (larger than 200 nm) can yield mono-dispersed layer or a layercomprising 2 sub-layers. The particle dispersions are based on ⅓ waterand ⅔ methanol.

Thus, it is assumed that the concentration of the particles allowscontrolling the number of sub-layers. Moreover, it is assumed that thesize of the particles affects the structural packing of the particleswithin a layer (hcp and ccp).

FIG. 30 shows a schematic presentation of a 6 composite material 3000.Each layer can be a multi-particle layer or a mono-dispersed layer. Anexample of a composite material 3000 can comprise polystyrene particlesof 320 nm, 260 nm, and 220 nm diameter in layers 3010, 3020, and 3030,respectively. Layer 3040 can include 160 nm PS particles and/or 160 nmsilica particles. Alternatively, layer 3040 can include 140 nm PMMAparticles. Layer 3050 can include 140 nm PMMA particles, 130 nm PSparticles, or 110 nm PMMA particles. Layer 3060 can comprise 110 nm PMMAparticles. In some embodiments, layer 3060 comprises 260 nm PSparticles.

FIG. 31 shows a 9-layer composite material 3100 that includes two 5layer gradients. The particles of the various switch from hcpconfiguration to ccp configuration and back as the size changes. Allparticles are made of polystyrene with —COOH functionality. All layersindicated as mono-dispersed layer can also be multi-particle layers andvice versa, which may not change the packing structure. In particular,gradient structure 3100 includes a layer 3110 of 130 nm particles, alayer 3120 of 160 nm particles, a layer 3130 of 220 nm particles, alayer 3140 of 260 nm particles, and a layer 3150 of 320 nm particles. Aninverted sequence of similar layers follows layer 3150.

As can be seen in the lower right corner, smaller particles can fillloosely packed areas of larger particle layers, thereby initiatingislands of specifically packed particles. The packing structure canassimilate within close packed sub-layers.

FIG. 32 shows a composite material 3200 with an alternating gradientdirection. Specifically, the composite material 3200 includes 17 layersthat form four regions of non-alternating gradients based on a change inparticle size of neighboring layers of about 20%. All particles arepolystyrene nanospheres with —COOH functionality. Only a single layer ofparticles is shown for each of the three larger particles layers 3210,3220, and 3230 as well as for the layer of smallest particles 3250. Amulti-particle layer 3240 of two densely packed sub-layers is shown.

The composite materials of FIGS. 30 to 32 can be considered to includedensely packed particle structures if one assumes one of the layers tobe representative for a multi-particle layer. Alternatively oradditionally, one can apply to the sides of the gradient structures toform a composite material with gradient structure and densely packedparticle structures.

As described above, any of the described composite material can furtherinclude core-shell particles as, for example, described in connectionwith FIGS. 11, 13, 14, 17, 22, and 24 as a separate layer(s) and/or aspart of the gradient layer structure itself or densely packed particlestructures. For example, filled core-shell particles of polystyrene canreplace the layers of larger particles, e.g., of the 320 nm, 260 nm and220 nm particles of FIG. 31.

In general, composite materials can include, for example, layers ofmono-dispersed particles, layers of mono-dispersed core-shell particles,multi-particle layers, multi-particle layers including sub-layers ofcore-shell particles, multi-core-shell particle layers, andmulti-core-shell particle layers including sub-layers of non-core-shellparticles.

In some embodiments, the composite materials based on layers ofmono-dispersed particles, layers of mono-dispersed core-shell particles,multi-particle layers, multi-particle layers including sub-layers ofcore-shell particles, multi-core-shell particle layers, andmulti-core-shell particle layers including sub-layers of non-core-shellparticles can be formed with or without intermediary material.Additionally or alternatively, intermediary material may be only usedfor binding layers of the larger (or smaller) particles of, e.g., agradient layer structure. Moreover, intermediary material may be onlyused in some areas and not in others.

In various applications, the composite materials based on layers ofmono-dispersed particles, layers of mono-dispersed core-shell particles,multi-particle layers, multi-particle layers including sub-layers ofcore-shell particles, multi-core-shell particle layers, andmulti-core-shell particle layers including sub-layers of non-core-shellparticles can be applied to devices such as containers as shown in FIGS.15 and 24 as examples for waste receptacles. These composite materialscan be further applied to fibers and used in connection with textiles asdiscussed in connection with FIGS. 16 and 17. Textile applications caninclude textiles for use in firefighting, law enforcement, military,defense, sports, and fashion. Such cloth or film can be suitable forforming uniforms, helmets, helmet liners, helmet liner pads etc. thatexhibit the beneficial effect of reacting to environmental changes in apredetermined manner. Specific examples can include inner liners foruniforms or jackets that can be attachable and/or fused into the cloth.

Sports impacts are a significant cause of injuries for athleticparticipants. Applicant believes the force of a sports impact behavessimilarly to blasts and other impacts described in detail above.Therefore, embodiments of the present invention may be used to mitigateinjuries caused by impacts. Textiles, pads, protective equipment,sporting equipment and other items may be coated for additional strengthand impact protection during sporting activities. Textiles andprotective gear may preferably use embodiments of the present inventionto improve on existing impact protection for athletic participants.Examples of sports equipment that may use embodiments of the presentinvention may include, but are not limited to, gloves, jerseys, pads forvarious body parts, jackets, pants, shorts, shirts, socks, shoes, hats,undergarments, swimwear, athletic supporters, braces and wristbands.These types of articles may be coated according to embodiments of thepresent invention. This may allow for flexible materials with increasedprotection against sports impacts.

Additionally, various sporting equipment may be coated to provideadditional strength and impact protection. Embodiments may be applied toone or more surfaces or portions of surfaces on sporting equipment.Examples of team sports equipment that may use embodiments of thepresent invention may include, but are not limited to, lacrosse shafts,lacrosse heads, lacrosse helmets, ice skates, roller skates, rollerblades, hockey sticks, hockey helmets, hockey pucks, baseball helmets,baseball bats, baseball gloves and catcher's mitts, batting gloves,catcher's masks, catcher's gear, field hockey sticks, cricket bats,football helmets, football face masks, upper body armor, shoulder padsand wrist guards, mouth guards, cleats, and ankle, knee and shin guards.Examples of individual sports equipment that may use embodiments of thepresent invention may include, but are not limited to, bicycles, toinclude bicycle seats, handle bars and handle bar tape and padding,suspension and struts, and wheel spokes and rims, cycling helmets,cycling gloves, golf clubs, golf tees, tennis rackets, squash rackets,racquetball rackets, badminton rackets, skateboards, snowboards, skis,ski poles, bindings, ski and snowboard boots. Other examples mayinclude, but are not limited to, riding crops, saddles, power sporthelmets, bowling balls, billiard balls, billiard cues, gymnasticsequipment, kayaks, canoes, boat hulls, snorkeling gear, scuba gear,fishing rods, fishing reels, fishing lures, paintball guns, airsoftguns, balls for various sports, shoes for various sports, sunglasses,exercise equipment, boxing gloves, and yoga mats. Exercise equipmentsuch as treadmills and components of weight training machines and crosstrainers can also use the shock absorbing qualities of the invention.

The articles themselves may be coated or may include a layer of coatedmaterials within the articles. For example, in a protected jersey, alayer of coated fabric may be sandwiched between layers of traditionalfabric or the traditional fabric may be coated according to embodimentsof the present invention. Part of all of a piece of equipment may beused with embodiments of the present invention. For example, the head orthe handle of a golf club may be coated, but the shaft may not becoated, or the handle of a baseball bat may be coated, or it can extendover the entire surface of the device.

The invention can also be employed in the area of medical devices forsuch things as neck braces and joint braces. Reduction in impactprotection may prevent further injuries.

Additional applications, can involve the suppression of shock waves(including shock waves) in pipes. Shock waves are, for example,generated through valve operation in oil pipelines as discussed inconnection with FIG. 18. The composite material can further be appliedto surfaces that require impact resistance. Examples include housing ofhand held devices, helmets, vehicles or components thereof, as discussedin connection with FIGS. 19, 21 to 24. The composite material in thoseapplications can be applied as a coating and/or provided as a liner. Thecomposite material can further be used in connection with cushions, forexample, the helmet pads shown in FIG. 21.

In the following, a large variety of materials are discussed that can beapplied in the composite material, specifically, for the solid particlesand core-shell particles. In general, the composite material can includeparticles of the same (single material system) or various differentmaterials. In various embodiments, suitable particles can comprisesilica; porous silica; aluminum hydroxide; polymeric materials; ceramicpolycarbonate; metal and metal alloy spheres; perlite, carbonate;bicarbonate and halide salts; ceramics; silicates; chelators, such as,for example, calcium or EDTA; foams or foam generating reagents, or acombination thereof.

Fire suppression can be achieved with particles comprising one or moreof potassium bicarbonate, aluminum, magnesium hydroxide, surfactants,aluminum hydroxide, potassium bicarbonate, halocarbons, potassiumiodide, lithium carbonate, sodium carbonate, sodium hypochlorite,potassium nitrate, magnesium hydroxide and various other hydrates,fluorocarbon surfactants, hydrocarbon surfactants, hydroflurocarbons(HFCs), pentabromodiphenyl ether, antimony trioxide, halocarbons,chlorinated and brominated materials (polybrominated diphenyl ether(PBDE or DecaBDE, OCtaBDE, PentaBDE), polybrominated biphenyl (PBB) andbrominated cyclohydrocarbons), and urethane.

For example, core materials that can be used for fire retardance orsuppression include hydroxides and hydrates, halocarbons, carbonate,bicarbonate, halide and nitrate salts, polybrominated materials,surfactants and hydrofluorcarbons. In particular, aluminum hydroxide canbreak down under heat to provide two primary methods for extinguishing afire ball associated with a bomb blast. First, it expels water vaporupon thermal breakdown which assists in quenching the fire.Additionally, the thermal breakdown process is endothermic and can thusabsorb a large amount of heat resulting from the blast zone. Stillfurther, the resultant material, after break down is an alumina (Al2O3),the presence of which can form a protective layer against the spread offire. Still further, the inert gases produced (water and carbon dioxide)can also act as diluents in the combusting gas, effectively lowering thepartial pressure of oxygen which slows the reaction rate.

In applications coupled with textiles, Tetrakis(hydroxymethyl)phosphonium salts can be used as core material

Moreover, ZrO2 eruptively generated aerosol can serve as theanti-explosion and fireproof agent, and therefore, can be applied insecurity applications.

In some embodiments, Hydroflurocarbons (HFCs) can be used for firesuppression. In particular, a series of HFCs are commercially availablefrom DuPont® that offer fire suppression with little or no ozonedepletion. In some embodiments, pentabromodiphenyl ether can be used asa core fire retardant (eventually in conjunction with antimonytrioxide). Still further, halocarbons can also be used as flameretardants core materials.

In some embodiments, chlorinated and brominated materials can also beused as fire retardant core materials. These materials can releasehydrogen chloride and hydrogen bromide during thermal degradation. Thesereact with H* and OH* radicals in the flame resulting in the formationof inert molecules and Cl* or Br* radicals. The halogen radicals havelower energy than H* and OH* and therefore reduce the propagation of theflame (reduction in oxidation potential). Antimony can also be used withhalogenated flame retardants. Brominated flame retardants are producedsynthetically in over 70 variants and are considered to be effectiveflame retardants. Any of the three classes of the brominated flameretardants can be separated into three classes or families:polybrominated diphenyl ether, polybrominated biphenyl, and brominatedcyclohydrocarbons.

Fluorocarbon surfactants and hydrocarbon surfactants can also be used asflame retardants. For example, the fluorocarbon surfactants disclosedand described in U.S. Pat. Nos. 4,090,967 and 4,014,926, the entiredisclosures of which are hereby incorporated by reference, can be usedfor coating gas lines and gas containing receptacles. These materialscan produce foam that spreads over a surface, effectively suppressingthe vaporization of gasoline. These foams can have, for example, anexpansion ratio of between 50/1 to 1000/1. In order to mitigate and/orremediate a radioactive or “dirty” environment, potassium iodide can beused as a core material to mitigate and/or remediate, for example,radioactive iodine 131, which is known to cause thyroid cancer. Othercore materials suitable for use in radioactive remediation include theknown family of chelators. Chelators are materials that can selectivelybind to radioactive metals. Two exemplary chelators commerciallyavailable in relatively large quantities are calcium and EDTA. In someembodiments, one or more particle layers of the composite material cancomprise an inert material, such as, for example, a porous silicaparticle. To that end, porous silica can offer exceptional absorptioncharacteristics.

Foam generating composite materials can be applied in applications suchas petroleum/oil based conveyance systems, refining operations, chemicalconveyance systems, and storage systems (e.g., as clotting or sealingmaterial). As core-materials or particle materials, the foam generatingcomposite material can then include, for example, epoxy materials (resinand hardener), which requires activation, an activating material, and afoaming agent. In addition, a reinforcing material, e.g., carbon fiberscan be provided to be penetrated by the foam. Exemplary foaming agentsinclude Telomer-based materials such as fluorosurfactants, aqueousfilm-forming foam (AFFF), alcohol-resistant aqueous film-forming foam(AR-AFFF), fluoroprotein (FP), film-forming fluoroprotein (FFFP), andalcohol-resistant film-forming fluoroprotein (AR-FFFP).Fluorosurfactants are based on perfluorinated telomer chemistry. Foamingagents can further include polyurethane, polyethylene, cross-linked,polystyrene, and urethane.

Composite materials for helmet liners or helmet liner pads can include,for example, latex based foam systems that require a latex solution asdissolved polymer, the foaming agent, a curative and a gel, as well as afire retardant (e.g., one of the polybrominated class).

In some embodiments, the composite material can provide shieldingagainst RF signals to assist in the prevention of a remote detonation.For example, an RF shielding layer can be provided by incorporating aconductive element in one or more of the particle layers. A number ofmaterials are known to be capable of providing RF shielding, including,for example, copper and nickel. By incorporating electrically conductiveand/or electromagnetic radiation absorptive particles into one or morelayers, an RF signal can be shielded thus inhibiting the ability forremote detonation of an explosive device.

In some embodiments, one or more layers can comprise a piezoelectricmaterial. According to this embodiment, the piezoelectric material caninteract with vibrations of the surrounding environment to produceelectricity. For example, acoustic waves could be used to attenuate amaterial designed as described so that piezoelectric materials in one ofthe layers are utilized to produce electricity. The produced electricitycan then be harnessed for use internally by one or more layers of thecomposite material or can be used external to the material.

It should be understood that any one or more layers of the compositematerial can be customized to interact with or react to changes in thesurrounding environment in a predetermined manner. To that end, theselection of materials depends on the particular predeterminedinteraction or reaction that is desired.

Production of particles, such as, for example, core-shell particles, cancomprise a solvent cast process, a continuous solvent cast process, anextrusion process, and a combination thereof. In some embodiments, sucha process can require that the material and/or precursor materials be atleast partially soluble in a volatile solvent or water; remain stable insolution with a reasonable minimum solid content and viscosity; and becapable of forming a homogeneous film and/or an in-situ gradient, andreleasing from a casting support.

For selected core or agent materials, the microcapsules can bemanufactured by conventional micro-encapsulation technique.Micro-encapsulation is defined as a process by which clusters of asolids, liquids or gases are packaged within a shell material.Micro-encapsulation is commonly distinguished as either a chemical orphysical process. Both processes can be used to produce the core shellstructures.

In some embodiments, the microcapsules can be formed from a conventionalpolymer or polycarbonate composition. It should be appreciated that suchpolymers and polycarbonates are further customizable in that they can beproduced with a variety of physical attributes. For example,microcapsules can be manufactured having specifically desired strengths,elastic coefficients, colors, and thicknesses. The use of polymers canalso offer energy absorbing characteristics as they decrease deflectionof compression and sound waves. Further, polycarbonates can be used as atransparent material and ceramic/polycarbonate composite materials canbe used, for example, in specific applications where increased levels ofshielding (emf, induction, radiation etc.) are desired.

Exemplary chemical micro-encapsulation techniques that can be used tomanufacture the encapsulated core-shell particles includepolycondensation (interfacial polymerization), colloidosome formation,polymer precipitation by phase separation, layer-by-layerpolyelectrolyte deposition, surface polymerization and copolymer vesicleformation. Likewise, exemplary physical micro encapsulation techniquesinclude centrifugal extrusion, fluid bed, a Wurster process, and pancoating. In addition, centrifugal extrusion techniques can be used toproduce larger particles, such as those ranging from about 250micrometers to about a few millimeters in size.

In addition to the microencapsulated core-shell particles describedabove, one or more layers of the composite material can also compriseany of the core materials described above without the core or shellencapsulation coating. In addition, one or more layers can also comprisethe microencapsulated shell coatings described above, in the absence ofthe core material.

The shell of a core-shell particle can be produced using a variety ofprocesses. In various embodiments, the process used for the productionof a core-shell particle can comprise FBE powder coating/lining;metallizing; electrostatic spray; dip coating; organic coating; parylenecoating; spray coating; screen coating; roller, spin coating, extrusionprocesses, passive adsorption, covalent coupling, or any combinationsthereof. In some embodiments, the process used for the production of acore-shell particle can comprise the one or more of the followingtechniques and/or material systems: polymers, for example, but notlimited to baked phenolic, elastomeric urethane, epoxy, polyurethane,vinyl ester, polyester, polystyrene, or any combinations thereof.

It should be appreciated that any individual encapsulation method can besuitable for the production for particle sizes having a specific sizerange and that one or more methods can be suitable for the production ofa specific size particle. Exemplary encapsulation methods and particlesize ranges are detailed in Table 2 below. It should be appreciated thatthe recited ranges are not limiting and can vary.

TABLE 2 Encapsulation Method Size Range (μm) Physical Methods Stationaryco-extrusion 1,000-6,000  Centrifugal co-extrusion 125-3,000  Submergednozzle co- 700-8,000  extrusion Vibrating nozzle >150 Rotating disk  5-1,000 Pan Coating >500 Fluid bed   50-10,000 Spray drying 20-150 Chemical Methods Simple/Complex coacervation 1-500 Phase Separation1-500 Interfacial polymerization 1-500 Solvent evaporation 1-500 In-situpolymerization 1-500 Liposome 0.1-1    Sol-gel methods 0.1-1   Nanoencapsulation  <1

The multilayered composite material can be manufactured by a number oftechniques. Initially, once the selection of particles and thecorresponding particle sizes are determined for a given layer, theseparticles can be suspended in a liquid vehicle system or medium to forma batch composition for the given layer. The batch composition can thenbe used to form a layer of the material on a substrate. In oneembodiment, it is contemplated that the successive layers of thecomposite material can be applied as a film or coating to the substrate.Accordingly, a batch composition for each given layer can be providedand successively applied to a surface of the substrate. Depositiontechniques can include, for example, chemical vapor deposition,electrophoretic deposition, plasma enhanced vapor deposition,spin-coating, dip coating, flexographic printing, spread coating,sequential spray, foaming, spray coatings, casting, slurry basedprocesses, and sequential processes. Those techniques can allow, forexample, the production of waste receptacles and transparent liners. Dipcoating, flexographic printing, and knife-edge layering can be applied,for example, for the production of commercial quantities. Spin-coatingcan be used, for example, to produce samples for experiments.

In some embodiments, it is also contemplated that the composite materialcan be manufactured as a stand-alone article without requiring it to beapplied to or supported by a substrate. For example, successive batchcompositions can be used to form multiple plies of a stand-alone film.Alternatively, batch compositions can also be used to manufacture moldedarticles such as for example, injection molded, extrusion molded, andblow molded articles.

The batch composition for providing a given layer of the compositematerial can comprise a plurality of the desired particles suspended ordispersed in a suitable liquid vehicle system or medium. The liquidvehicle system can be formulated based upon any one of the followingstabilization techniques including electrostatic stabilization, stericstabilization, electrosteric stabilization, depletion stabilization,stabilization by masking van der Waals forces, and stabilization byhydration forces. The stabilization mechanisms work by preventing orhindering the flocculation of the particles in suspension. In someembodiments, it is preferred for the liquid vehicle stabilizationtechniques to be an electrostatic or electrosteric stabilization.Electrostatic stabilization uses ions in solution to generate likecharges on the particles in suspension. Electrosteric stabilization usesa charged polymer that adsorbs on the particle surfaces, causingdouble-layer repulsion. Either technique can be used to stabilize asuspension. Further, exemplary particles in liquid vehicle dispersionscan be produced in aqueous form or from other suitable mediums that havelow volatility and suitable thermal stability, such as for example,ethylene glycol.

For electrostatic stabilization, an acid or base (the choice of whichcan be dependent upon the charge of the particle surfaces) can be addedto an aqueous suspension. The addition can adjust the pH of thesuspension, which can affect the charge on the particle shear planes,i.e., the zeta potential. If the particle surface has a positive charge,adding an acid to the suspension decreases viscosity effectivelyincreasing the magnitude of the zeta-potential. When acid is added tothe suspension, the particle shear planes develop a net negative charge,causing the particles to repel each other. The opposite is true for asuspension of negatively charged surfaces to which a base can be addedto give the particle shear planes a net positive charge and in order tosuitably disperse the particles in the suspension.

For electrosteric stabilization, the presence of a dispersant candirectly influence the stability of the suspension until the particlesurfaces are completely covered. Dispersants can be added in relation tothe particles surface area, charge and size of the particles ensuringthe correct amount of coverage. For example, in some embodiments, apolyelectrolyte dispersant should have the opposite charge of theparticle surface being dispersed. The addition of a polyelectrolyte canchange the isoelectric point allowing a dispersion to result without theneed to adjust the pH of the suspension. When added to a suspension nearthe point of zero charge, the water used in the suspension can have agreater affinity for itself than the polymer, and hence the polymer canadhere to the particle surfaces. To prevent coagulation, an ionicsolution can also be added to an electrosterically stabilized suspensionto counter act the charge buildup. To that end, it should be understoodthat a stable suspension can be important as it can allow a highersolids loading with lower apparent viscosity than an unstable suspensioncan allow.

Still further, the batch compositions can comprise additives such ascolorants, biocides, surfactants, plasticizers, binders, dispersants,acid, base, pore formers, and the like. Additionally, it should also beunderstood that the batch compositions can be formulated to providetransparent, translucent, or even opaque composite materials. Forexample, it can be desired for the composite material to be transparent.This can enable the manufacture of, for example, a transparent film,liner or, alternatively, a composition that can be applied to glass orsimilar substrates without affecting the pre-existing transparency ofthe substrate upon which it is applied. Alternatively, it can bepreferred for the composite material to have a predetermined colorsuitable for use in forming stand-alone articles or coatings havingcertain aesthetic appearances.

As summarized above, it is further contemplated that the compositematerials can be used in a variety end use applications including, forexample, military, energy and related infrastructure, electronics,sensors and actuators, lubricants, medical applications, catalysis,structural materials, ceramics, civil engineering applications,aerospace, automotive applications, textile and antiballistic materials.In some embodiments, it is contemplated that the composite material isparticularly well suited for use as or in combination with anantiballistic material.

In some embodiments, a composite material can be applied onto thesurface of any desired object in order to provide the blast energyabsorption and any secondary blast mitigation effects described herein.For example, the material can be applied to the inside surface of atrash receptacle. Alternatively, the material can be provided in theform of a stand-alone film that is suitable for use in manufacturingliners that can be removably placed inside pre-existing trashreceptacles. The liner can be manufactured having any predeterminedcolor. Alternatively or in addition, the liner can also be transparent.Still further, it is also contemplated that the composite material canbe used to form the trash receptacle itself thus eliminating the need toapply either a separate coating or a liner in order to provide the blastenergy absorption and any secondary blast mitigation effects describedherein. Once again, the manufactured trash receptacle can also have anypredetermined color or be transparent.

Thus, the response of the composite material can be considered to besmart in that it does have a designed or engineered response to anexternal stimulus. Specifically, the properties of the compositematerial adapt in response to the external stimulus. The compositematerial can be further provided to be multifunctional, e.g., includemultiple features such as absorption of compression waves, mitigation offire, remediation of biological systems etc.

EXAMPLES

The invention is further described in the following examples, which donot limit the scope of the invention described in the claims.

Prophetic Example 1 Exemplary Batch Composition

In an exemplary embodiment, a composite material could be comprised of aplurality of tape casted layers. The tape casting could be used to applythe composite material layers to a pre-existing substrate or to form astand-alone multi-layered composite material. An exemplary andnon-limiting batch composition that could be used to prepare eachsuccessive layer of the composite material is set forth below in Table3:

TABLE 3 Component wt % Function Microspheres 55.66 Layer 1 Xylene 18.55Solvent Ethanol 18.55 Solvent Butvar 98¹ 4.08 Binder Menhaden 1.12Dispersant oil Santicizer 1.02 Plasticizer 160² UCON³ 1.02 Plasticizer¹Commercially available from Electron Microscopy Sciences Hatfield,Pennsylvania; ²Commercially available from the Ferro Corporation, WaltonHills, Ohio;

Based upon the formulation set forth in Table 3, the microspheres,solvents and dispersant can first be mixed in a ball-mill forapproximately 24 hours. After mixing in the ball mill, the binder andplasticizer component can then be added to the ball mill and theresulting mixture can be mixed for another 24 hour period. After mixingis completed, the composition can be tape cast onto a coated paper or asteel belt to form a particle layer. The tape casting can be performedby using a commercially available tape casting apparatus such as aUnicast 2000. The tape cast layer can then be allowed to dry naturallyunder ambient conditions. This process can be repeated using batchcompositions comprised of particles having differing median particlesizes until a desired number of particle layers have been tape cast toform the particle size gradients and densely packed particle structuresdescribed herein.

Prophetic Example 2 Use as a Blast Wave Absorbing Material

With reference to FIG. 1, the material of the composite material can beused as a blast wave absorbing material. For example, a materialmanufactured according to prophetic example 1 can be disposed on theinterior surface of a waste receptacle so that the layer 110 comprisingthe largest median particle size is oriented to be the first layerexposed to the impact of the bomb blast shock wave. The layers comprisedof smallest particles, layer 170, would be position or located adjacentto the waste receptacle wall. The layers 110, 120, and 130 can becomprised of particles having the core-shell microstructure as depictedin FIG. 11. The shell 1120 of the material can be pliable such that itcan deform upon impact of a bomb blast (shock wave 20). The particlecores can be comprised of one or more blast mitigating materials, suchas sodium hypochlorite, potassium nitrate, and the like. Layer 140 cancomprise a RF shielding material (such as copper, nickel, copper andnickel alloys, cermets, and the like). The adjacent remaining layers150, 160 and 170 can be comprised of particulate materials, such as aporous silica, whose median particle size distribution allows asufficient increase in the interlayer particle contact points toefficiently reduce the impact 105 across the material 100 and theremaining layers (150, 160 and 170).

Upon impact of the shock wave 20, the core-shells in layers 110, 120 and130 can deform and a portion of the energy associated with the bombblast can be removed from the system due to this deformation. As theshells deform, they can also apply pressure to the adjacent particlesupon which they contact, thus, transferring impact energy to the energyrequired for deformation and angular pressure on its neighboringparticles. Ultimately the shells 1120 deform to a point where shellrupture occurs releasing the core fire retardant materials directly intothe blast zone. As the core-shell particles rupture in successivelayers, the cores from different particles are introduced into the blastzone, which can further enable, if desired, more complex systems orcombinations of systems to be introduced, thus allowing sequentialreactions to occur in a user defined manner. The staggering of corematerials in a pre-designed manner allows sequential reactions whose sumreaction is greater than their individual contributions.

In addition to the core-shell rupturing, as the shock wave 20 traversesacross the first layer 110, it would reach the interface between thefirst layer 110 and the second layer 120. As the particles comprisingthe first layer 110 are larger than the particles populating the secondlayer 120, there also exists at the interface an increase in surfacecontact points. As in the case of the first layer 110, the impactenergy, deforms, compresses and re-orientates the individual particlescomprising the second layer 120 resulting in a reduction of the energyof the impact 105. The deformation, compression, re-orientation andtransfer of energy relationships continues across the cross section ofthe material 100 and through subsequent layers from layers 120 to 130,130 to 140, 140 to 150, 150 to 160 and 160 to 170.

Prophetic Example 3 Experimental Design

In some embodiments, a composite material could be comprised ofencapsulated materials having particle sizes of 500 nm, 5 μm, and 50 μm.The mean particle diameter and the tensile strength of a particulatefilled rigid polyurethane resin at a given volume fraction can beexpressed as a linear relationship. In addition, the ability of theparticle to flow and compress decreases with average particle size,while strength and transverse rupture strength (TRS) increase withdecreasing particle size.

A unique slope of the linear relationship between friction angle andvoid ratio was identified for monosize specimens of varying particleshapes. It was also observed that the friction angle decreases as theaspect ratio increases provided that the void ratio of the two specimenswas the same. The friction angle was proportional to the coordinationnumber for monosize specimens regardless of individual specimen size.

Testing protocols for a composite material produced in accordance withthe present invention can include: 1) shock tube analysis wherein shockwaves are generated by the rupture of a thin diagram separating high andlow pressure gases, wherein samples are mounted at the end of a tube; 2)simulations of blast effects using small (e.g., gram range) explosivecharges, scaling models, and optical shock wave imaging techniques,wherein shock waves are simulated using scaling law; and 3) detonationtechniques wherein the velocity at which a detonation wave travelsthrough the explosive product is determined, typically in the range offrom about 2,000 to about 8,000 m/s.

It should be appreciated that several types of experimental designs canbe investigated. For example, experimental designs based upon particlescan be investigated. The primary input of energy occurs via theinteraction of clusters, molecules, atoms, or ions with a surface. Theamount of transferred energy ranges from eV to a few keV. Energydissipation processes can be studied by means of spectroscopictechniques and laser interferometry. These experiments are not timeresolved, but rather quasi-stationary. Dynamics can also beinvestigated. For example, a dynamic observation can be made of theenergy dissipation process requiring excitation of a surface via anultra-short laser pulse providing photon energies of a few eV. Using apump-probe technique with a second delayed pulse can probe the reactionof a system upon excitation. Analysis techniques can includediffraction, spectroscopic techniques, laser interferometry, and variousimaging techniques. Still further, effects of friction can also beinvestigated. This can include a study of the transport of particles andelectrons at surfaces and in thin layers, particularly energydissipation due to both mechanical friction and friction due toscattering at the surface and interfaces. Friction analysis techniquescan include spectroscopic and imaging techniques.

Example 4 Preparation of Multilayer Composite Materials

Various types of multilayer composite materials were produced byspin-coating various layers of particles on a polycarbonate substrate.The polycarbonate substrate had a thickness of about 1 mm but in generalthe thickness of the substrate can vary and be adapted, for example, tothe application.

To increase the adhesion of the first layer of particles, thepolycarbonate substrate was irradiated with a mercury lamp using theultraviolet transition at 253.7 nm. In the presence of air, the oxygenof the air reacted under the irradiation to create oxygen containingradicals at the surface of the polycarbonate. The final product of thereaction is an organic acid functionality at the surface that rendersthe surface hydrophilic and provides a hydrogen-bonding surface uponwhich the layers of the nanostructures were built. The time period of UVirradiation was about 30-60 minutes, usually about one hour.

After irradiation, the polycarbonate substrate was transferred to a spincoater and a first layer of particles was deposited. As particles,nanospheres were provided with carboxylic acid functionality on thesurface (polystyrene particles) or polar in nature (silica and PMMA).

All nanospheres were provided in a mixture of 25% water and 75%methanol. Due to the small size and their repulsion due to theirpolarity, most of the nanospheres did not aggregate. If aggregation waspresent, particles settled out of the suspension. Then, the dispersionwas placed in a sonicator to break up the aggregates and redisperse thenanospheres. All dispersions contained 2.5% nanospheres, therebyproviding one to two layers of nanospheres in the film. If moreparticles in a layer were desired, the particle concentration wasincreased to 5%.

The spin coater was operated in a two-step sequence after 75 μl ofnanospheres suspension were placed on the substrate. The first steplasted 5 seconds and the substrate was spun at 300 rpm to spread thedispersion over the entire substrate. The spin coater speed was thenincreased to 4000 rpm (2000 rpm, if the 5% solution was used) for oneminute.

The substrate with the layer was removed and heated at 50° C. for 5minutes to aid in evaporating the solvent. In a test run, five differentlayers of nanospheres were added before the heating step, which workedjust as effectively. The multilayer composite material was built up inthis way until the desired number of layers was deposited. Beforetesting, the samples were stored for a day. The concentration of 2.5%corresponded to a dilution of between 1:4 and 1:8 of the provided stocksolutions.

The spin coating proved to be a good technique to produce lab samples ofvarious gradient structures and densely packed particle structures. Spincoating allowed generating multilayer gradients using monolayers ormultiple layers of each different size particle used in the gradient byadjusting the concentration of nanoparticles in the dispersion solutionand/or the spin at which the substrate was coated. The layer structureswere confirmed by profilometry, force microscopy and electron microscopyas discussed below.

The following samples of gradient structures and densely packedparticles structures were produced on polycarbonate substrates accordingthe above described procedure:

Samples #01 and #02: Polycarbonate-130-160-220-260/130-160-220-260/etc.The set of four layers was repeated eight times (32 layers in total).

Samples #03/#04:Polycarbonate-130-160-220-260-220-160/130-160-220-260-220-160/etc. Theset of six layers was repeated five times (30 layers in total).

Samples #05/#06:Polycarbonate-130-160-220-260-320-400-320-260-220-160/130-160-etc. Theset of ten layers was repeated three times (30 layers in total).

Sample #07: Polycarbonate-150-150-150-etc. The 150 nm layer was repeated30 times (30 layers in total).

Sample #08: Polycarbonate-320-400/320-400/320-400/etc. The two layerswere repeated 13 times (26 layers in total).

(Sample #09 as a duplicate of sample #8 was not produced.)

Sample #10:Polycarbonate-400-320-260-220-160-130/400-320-260-220-160-130/400-320-etc-.The set of six layers was repeated four times (24 layers in total).

The samples were produced under conditions that created layers having athickness of one or two layers particles for each size. Thenanoparticles were characterized by their diameter in nm. Allnanospheres were solid polystyrene particles, except that the 400 nmparticles were hollow polystyrene particles and the 150 nm were solidsilica particles. Alternative embodiments may include solid 400 nmparticles.

The carboxylic acid functionalized nanoparticles, e.g., polystyrene orsilica, formed a “bound” film by an assumed interparticle hydrogenbonding. Essentially, there were electrostatic interactions among theparticles that made the layers stay together. This was confirmed byremoving an intact film from the substrate with a piece of tape.

The coatings were transparent or, at the very least translucent.

In FIG. 33, the particle size is plotted for the first twelve layers toillustrate the gradient of the particles size across the multilayerstructure of sample #10. The particle size varies in a saw-tooth-mannerfrom the largest particle to the smallest 130 nm solid nanosphere. Asaw-tooth 3310, i.e., a transition from large to small particles,corresponds to a region with a gradient directed in the same directionand all saw-tooth have the gradient in the same direction. In FIG. 33,the 400 nm hollow spheres are indicated by circles 3320.

A cut view 3330 through the first two gradients is schematicallyillustrated in the top right corner of FIG. 33.

Accordingly, the surface of the composite material according to sample#10 is formed by the smallest particles.

In FIG. 34, the particle size is plotted versus the first 18 layers toillustrate the gradient of the particles size across the multilayerstructure of samples #05 and #06. The particles size varies continuouslyfrom the smallest 130 nm particles to the largest particles (the 400 nmhollow spheres are indicated by reference number 3420) via the particleswith the sizes 160 nm, 220 nm, 260 nm, 320 nm. Then the gradientdirection changes and the particle size decreases again down to thesmallest 130 nm particles via the particles with the sizes 320, 260 nm,220 nm, and 160 nm. Also in the structure shown in FIG. 34, the surfaceof the composite material is formed by the smallest particles. Combiningthe gradient structures (samples #1 to #6 and #10) and densely packedparticle structures (samples #7 and #8) can result in layered compositematerials with gradient structures and densely packed particlestructures.

Example 5 Impact Test of the Samples of Example 4

An impact tester was built using a weight (steel impactor) that wasdropped onto an assembly, e.g., a multilayer structure sandwichedbetween two polycarbonate plates. The assembly was attached below a tubethat housed the weight, which can be dropped from a predeterminedheight.

The impact tester comprised further a spring loaded sample mount with adynamic force sensor. The dynamic force sensor was configured to detectthe transmission of the shock through the assembly. Specifically, thesensor detected the arrival of the shock wave at, e.g., the edge of thegradient's substrate.

A comparison was performed between various assemblies: a) no sample/noplates at all, b) two polycarbonate plates without sample, and c) asandwich of two plates with one of the samples #01-#10 between theplates. Assemblies a) and b) were used as controls to provide a readingof the true force, the force transmitted through two pieces of blankpolycarbonate. The controls allowed for a measure of the effectivenessof the sample (assembly c) in attenuating the shock. Specifically, theweight impacted the top piece of polycarbonate, sending a shock waveinto the gradient film.

The plot of FIG. 35 overlays the three transmitted signals as measured.In particular, signal 3510 corresponds to the initiated shock wave asmeasured without sample and without plates, signal 3520 corresponds totwo polycarbonate plates without sample, and signal 3530 corresponds toa sandwich of two plates with an exemplary gradient sample between theplates.

As one can see, signals 3510, 3520, and 3530 differed in their time ofdetection and in the maximum of the signal. Thus, the sample delayed theshock wave and reduces its maximum.

For the various samples, the measurements were analyzed from anoscilloscope using the maximum force detected by the sensor, the widthof the force peak and the time delay of the maximum force. The data aresummarized in Table 4 below and ordered according to the reduction ofthe measured force.

TABLE 4 Width, Sample Max. Force, N ms Delay, ms Bare sensor 1334 0.16 —Polycarbonate x2 1156 0.27 0.10 # 1/#2 872 0.31 0.18 (averaged) #3/#4783 0.30 0.21 (averaged) #7 712 0.31 0.20 #10 712 0.30 0.21 #5/#6 6230.34 0.22 (averaged) #8 578 0.34 0.24

According to the measurement, samples #01 and #02 with a discontinuousgradient of small to large particles reduced the force the least.Structures with incorporated hollow particles reduced the force the morethan gradient structures with only solid particles. The densely packedparticle structure of two particle types (hollow core-shell and solid)in sample #08 with the most hollow particles reduced the force the most.Second best were samples #05 and #06, which comprised a continuousgradient and included the hollow particles of 400 nm diameter. Also thedensely packed particle structure of a single particle configuration insample #07 reduced the force.

Example 6 Analysis of the Surface and Structure of Multilayer CompositeMaterials

To analyze the surface and structure of gradient layers, two types ofgradient layer structures were produced using the method as described inExample 4. The types differed in the direction of the gradient.Specifically, five samples #11 with gradient320-260-220-160-130-160-220-260-320 and three samples #12 with gradients130-160-220-260-320-260-220-160-130 were produced. One of the goals ofthe analysis was to look at a cross section of the gradient layerstructure with an environmental scanning electron microscope (SEM) andestimate the number of layers for each layer of nanoparticles with aspecific size. The parameters of the production included a concentrationof 2.5% (1:4 dilution) and spinning at 4000 rpm.

FIGS. 36 to 39 show SEM images of the top surface and a cross-sectionfor samples #11 and #12. The SEM of FIG. 36 shows the largest (320 nm)particles as the top layer. The top layer is little disorganized. The260 nm layer below the top layer seemed closer to an hcp arrangement.

The SEM of FIG. 37 is the edge view of the same film carefully brokenand put into the microscope to look at the cross section, i.e., thebreak. The break was not a clean break. Most of the layers going throughthe gradient could be identified. Looking also at lower layers of thegradient layer structure, it was estimated that the parameters resultedin gradient layer structures comprising monolayers for each of theparticle sizes (herein also referred to as monolayer gradient).Accordingly, the applied deposition conditions (1:4 dilution and 4000rpm spin speed) generated the monolayer gradients.

Based on the SEM measurement, the thickness was estimated to be about900 nm. Due to the close packing in direction of the gradient, the sumof the sizes of the particles in each layer did not equal the measuredthickness.

As can be seen from similar SEM images reproduced in FIGS. 38 and 39,sample #12 was also produced as a monolayer gradient. That can be seen,for example, in the cross sectional view shown in FIG. 39. Based on theSEM measurement, the film was measured to be about 800 nm thick.

To confirm the thickness measurement, the films of samples #11 and #12were measured using a profilometer. A section of the film was removedand a stylus was moved across the film until it moved to the baresubstrate. Several measurements were taken and averaged to compensatefor variations in the film thickness and the quality of the glasssubstrate. The average thickness for sample #11 was 960 nm and theaverage thickness for sample #12 was 1030 nm. These values agree withthe SEM measurements and confirm the monolayer gradient structure.

Example 7 Hardness Test of Multilayer Composite Materials

To analyze the hardness of gradient layer structures, two types ofgradient layer structures were produced using the method as described inExample 4. The types differed in the direction of the gradient.Specifically, sample #13 included four alternating gradients (with 17layers in total) with particle sizes between 320 nm and 130 nm andbetween 130 nm and 320 nm. Sample #14 included two gradients (with ninelayers in total) with particle sizes between 130 nm and 320 nm and 320nm and 130 nm. The parameters of the production included a concentrationof 2.5% (1:4 dilution) and spinning at 4000 rpm. One of the goals of theanalysis was to characterize the surface hardness usingnanoindentation—a technique to measure hardness on the nanoscale.

Nanoindentation presses a pyramidal tip with dimensions of a few tens ofnanometers into the sample and measures the force applied as a functionof the depth to which the tip is pushed into the sample. Multipleindentations were repeated at the same location on the sample.Specifically, 19 cycles of indentation and removal were made for themeasurements. Measurements were made at two surface locations on thecomposite materials. Four different maximum force values at each surfacelocation were used to allow for different maximum depths for indentationinto the film.

FIGS. 40 and 41 show hardness plots for the samples #13 and #14,respectively, for a maximum force of 200 μN. Schematic representations4010 and 4110 of the samples #13 and #14, respectively, are included inthe top right corner of the plots and show that in sample #13 largeparticles form the surface, while in sample #14 small particles form thesurface. The plots are representative for a series of measurements.

The force-depth curves were converted to nanohardness and Young'smodulus data as a function of indentation depth. Young's modulus (E) isa measure of the stiffness of an elastic material such as a polymer. Itis the ratio of the stress over the strain in the film andexperimentally determined from the slope of a stress-strain curve.Nanohardness is defined as resistance to permanent or plasticdeformation at the nano-micro level. Hardness is a measure of resistanceto an indentation. Both properties are measurement technique dependentas there are different scales depending on the equipment used. Data fromnanoindentation generally correlates with, but does not exactly agreenumerically with measurements on a macroscale.

Arbitrarily, a depth of 200 nm was selected for averaging the values ofhardness and elastic modulus for the four different forces at thatpoint. The results for the two sampling sites on each of samples #13 and#14 were for sample #13: Hardness=0.050 GPa/0.045 GPa and Young'smodulus=1.75 GPa/2.48 GPa and for sample #14: Hardness=0.102 GPa/0.067GPa and Young's modulus=2.87 GPa/4.12 GPa. For comparison, theliterature values for polystyrene in bulk from are Hardness=0.15 GPa andModulus=2.2 GPa.

The derived nanohardness and Young's modulus seemed to depend on thegradient—although the effect is not large as the composite materialsonly comprised two gradient structures. The values for thesmall-to-large-to-small gradient differed from those of the oppositeorientation. The determined values were in the same range as those for abulk thin film of polystyrene, but the fact that the two samples weredifferent seemed to indicate that the packing of the nanoparticlesinfluences these properties.

It was further assumed that the gradient was better defined away fromthe edge, i.e., in the center. In general, the films appeared to beslightly harder than the bulk.

It is to be understood that while the invention has been described inconjunction with the detailed description thereof, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the scope of thefollowing claims.

What is claimed is:
 1. A sports equipment apparatus comprising: a firstlayer structure comprising a first plurality of densely packedsub-macroscale particles having a first mean diameter; and at least asecond layer structure comprising a second plurality of densely packedsub-macroscale particles having a second mean diameter that is differentfrom the first mean diameter, wherein the first layer structure and thesecond layer structure are applied to a substrate, and wherein thesubstrate is an article of sports equipment.
 2. The apparatus of claim1, wherein the first mean diameter is greater than the second meandiameter.
 3. The apparatus of claim 1, wherein the first mean diameteris less than the second mean diameter.
 4. The apparatus of claim 1,wherein the sub-macroscale particles are selected from a groupconsisting of: microscale particles, nanoscale particles, andcombinations thereof.
 5. The apparatus of claim 1, wherein a selectedone of the first layer structure and the second layer structurecomprises solid particles.
 6. The apparatus of claim 1, wherein aselected one of the first layer structure and the second layer structurecomprises hollow core shell particles that are configured to deform uponbeing subjected to the compression wave.
 7. The apparatus of claim 1,wherein a selected one of the first layer structure and the second layerstructure comprises hollow core shell particles that are configured torupture upon being subjected to the compression wave.
 8. The apparatusof claim 1, wherein a selected one of the first layer structure and thesecond layer structure comprises liquid filled particles that areconfigured to release a liquid upon being subjected to the compressionwave.
 9. The apparatus of claim 1, wherein the sub-macroscale particlescomprise particles selected from a group consisting of: polystyrene,silica and carbon.
 10. The apparatus of claim 1, further comprising aplurality of adjacent layer structures, each of the plurality ofadjacent layer structures including a plurality of densely packedsub-macroscale particles having a corresponding mean diameter, theplurality of adjacent layer structures disposed so that a mean diametergradient is formed across the plurality of adjacent layer structures.11. The apparatus of claim 1, wherein the particles are functionalizedprior to deposition.
 12. The apparatus of claim 11, wherein theparticles include carboxylic acid functionality.
 13. The apparatus ofclaim 11, wherein the particles are polarized.
 14. The apparatus ofclaim 1, further comprising an intermediary layer comprising a compositeof polymer and carbon allotrope.
 15. The apparatus of claim 14, furthercomprising an outer layer of the same composite.
 16. A method of makingan article of sporting equipment, the method comprising: depositing afirst plurality of sub-macroscale particles having a first mean diameterand suspended in a first liquid medium onto a substrate; subjecting thefirst plurality and the substrate to a first environment for a firstpreselected amount of time sufficient to cause the first liquid mediumto evaporate leaving a first layer structure of the plurality ofsub-macroscale particles on the substrate; depositing a second pluralityof sub-macroscale particles having a second mean diameter, differentfrom the first mean diameter, and suspended in a second liquid mediumonto first layer structure; and subjecting the second plurality, thefirst plurality and the substrate to a second environment for a secondpreselected amount of time sufficient to cause the second liquid mediumto evaporate leaving a second layer structure of the plurality ofsub-macroscale particles on the first layer structure, and wherein thesubstrate is an article of sporting equipment.
 17. The method of claim16, further comprising the action of irradiating the substrate so as tocreate an organic acid functionality on a surface of the substrate,thereby increasing adhesion of the sub-macroscale particles thereto. 18.The method of claim 16, wherein the sub-macroscale particles compriseparticles selected from a group consisting of: polystyrene, silica andcarbon.
 19. The method of claim 16, wherein the sub-macroscale particlescomprise particles selected from a group consisting of: solid, hollowand core shell, filled, unfilled, and filled in part.
 20. The method ofclaim 16, further comprising the action of functionalizing thesub-macroscale particles prior to deposition.
 21. The method of claim20, wherein the functionalizing action comprises providing thesub-macroscale particles so at to include carboxylic acid functionality.22. The method of claim 20, wherein the functionalizing action comprisespolarizing the sub-macroscale particles.
 23. The method of claim 20,wherein the sub-macroscale particles comprise particles selected from agroup consisting of: nanoscale particles, microscale particles andcombinations thereof.
 24. A medical device apparatus comprising: a firstlayer structure comprising a first plurality of densely packedsub-macroscale particles having a first mean diameter; and at least asecond layer structure comprising a second plurality of densely packedsub-macroscale particles having a second mean diameter that is differentfrom the first mean diameter, wherein the first layer structure and thesecond layer structure are applied to a substrate, and wherein thesubstrate is an article of medical equipment.
 25. A sports equipmentapparatus comprising: a layer structure that includes a plurality ofdensely packed sub-macroscale particles having a first mean diameter,wherein the first mean diameter is approximately 150 nm, wherein thelayer structure comprises at least approximately 30 layers of theparticles, wherein the layer structure is applied to a substrate, andwherein the substrate is an article of sports equipment.